Rain gauge accuracy rankings explained based on datasheets: tipping buckets, siphons, and weighing gauges

Required-depth analysis for rain-gauge accumulation totals

A transparent analytical-floor comparison of 80 rain-gauge accumulation products from Barani, OTT HydroMet, Lambrecht, KISTERS / HyQuest, Geolux, Vaisala, Texas/Campbell, EML/In-Situ/Campbell ARG314, Précis Mécanique, Observator/RIMCO, METER, Casella, Davis, Onset HOBO, Met One, RainWise, MicroStep / Meteoservis, AEM/FTS, CAE, Pronamic, Seven Sensor Solutions, Rika, Honde, Renke, and Tamaya/Ikeda. Each product is ranked by the minimum rainfall depth needed to reach a stated relative uncertainty target on a complete daily or event total. Readers who need short-window rate products should use the companion rain-intensity gauge accuracy ranking. The full input parameters, formulas, and worked sample calculations are in the appendix so any reader can verify the numbers independently. For background before reading the table, see the rain-gauge selection guide, the guide to rain-gauge types, common collector sizes and diameters, Rain Gauge Accuracy Tables, and rain-gauge accuracy and WMO/NWS standards.

Conflict-of-interest disclosure (read first). This analysis is prepared by Jan Barani, founder and CEO of Barani Design Technologies, manufacturer of the MeteoRain product family that appears in the comparison set. To mitigate bias: (i) every input value is drawn from publicly available manufacturer datasheets and operating manuals — no proprietary or vendor-supplied data — so any reader can re-evaluate the framework against the same inputs; (ii) conservative modelling parameters are applied uniformly across all products (U95 = 2σ_total, γ_s = 1 for siphon TBRs, B0/B0 boundary regime for accumulation regardless of telemetry); (iii) no vendor of any compared product has funded, reviewed, or approved this analysis. The full formulas and per-category sample calculations are in the appendix below; readers who suspect bias are encouraged to substitute alternative parameter values and verify the results.

New to the terms used in this comparison? The words “tipping bucket,” “siphon,” and “weighing gauge” refer to different rain-gauge measuring principles, while collector area comes from standard rain-gauge sizes and diameters. For the simple relationship between missed water, resolution, and percent error, see the rain-gauge accuracy tables; for standards context, see rain-gauge accuracy and WMO/NWS standards. Field results still depend on exposure, so the analytical floor should be read together with siting and mounting guidance.

What this ranking is and is not

What it shows

An intrinsic analytical floor from the instrument architecture: bucket size, siphon storage, transmitted phase code, and published amount-envelope floor. Useful for short-listing products that can reach a stated accuracy target on a complete daily or event total under best-case conditions. Standards context is discussed in rain-gauge accuracy and WMO/NWS standards.

What it does not show

Field accuracy. Wind under-catch, evaporative loss, debris, shielding, calibration drift, siting effects, spatial representativeness, durability, cost, power, maintenance burden, and communications are not included. Field-measured performance at any given site will always be worse than the analytical floor.

Read this before reading the table. The rankings below come from a deterministic mathematical model (analytical floor) using only public datasheet inputs. The same model would produce the same numbers if any other party ran it. Within any product class, the gauge that wins is the one with the smallest combined boundary-state and per-tip stochastic uncertainty — usually a function of bucket area and tip depth. The model does not pick winners by brand. Field performance is a separate question not addressed here.

Why accumulation needs its own ranking

The accumulation table should be read as a daily/event-total floor. A rolling active-rain window belongs in the companion rain-intensity ranking, not this total-accumulation ranking.

An accumulation total is a boundary-defined product. It usually starts when the gauge is dry and ends after the rain has stopped. At those event boundaries, no previous or next tip exists to anchor the leftover-water state — so a tipping-bucket phase code cannot bracket the residual. The MeteoRain IoT³ family therefore ties the wired version of the same hardware in the ranking below; the IoT³ phase advantage shows up in the companion intensity ranking, not here.

30 minutes is genuinely dual-use. A rolling 30-minute intensity warning during active rain belongs in the intensity ranking. A fixed 4:00–4:30 PM accumulation slot — for example a typical Florida summer afternoon thunderstorm — belongs in this accumulation ranking. The two rankings give different results for the IoT³ family even at the same nominal 30-minute horizon.

Visual summary before the table

This chart gives the fastest visual read of the ranking before the full table. Shorter bars mean less rainfall is needed before the product reaches the 1% uncertainty target. The chart is regenerated from the table so product names, including MeteoRain IoT³ labels, match the ranked rows below. Rows with non-applicable or unsupported 1% entries are omitted from the plot and remain in the table.

Figure 1. Required rainfall depth at the 1% target for 77 plottable rows from the 80-product Overall ranking table, generated directly from table values. Rows without a numeric 1% value are not plotted.

Overall ranking — all 80 products in one table

Sorted by required depth at 1%. Lower is better. The category badge in the product column shows the gauge family (TBR / Siphon / Weighing / IoT³ phase-aware). Note: the IoT³ phase-aware advantage does not apply to accumulation totals (see "Why MeteoRain IoT³ ties the wired version" below); IoT³ rows therefore tie the wired version of the same hardware in this overall ranking. Ties are marked with a "T" suffix on the rank.

Table navigation: scroll left and right inside the table box to see all columns. The rank and gauge columns remain pinned; notes and technical evidence columns sit farther to the right.

Overall rank	Gauge / output product	P_min at 1% (mm)	P_min at 2% (mm)	1% @30 min (mm/h)	1% @1 h (mm/h)	1% @3 h (mm/h)	1% @6 h (mm/h)	1% @24 h (mm/h)	Δ_res (mm)	Evidence layer	State detail	A (cm²)	d / d_eq (mm)	V_s (mL)	Why it ranks here
1T	IoT³ MeteoRain IoT³ 533 Classic (gen3)	6.36	3.12	12.73	6.36	2.12	1.06	0.265	0.0094 / 0.075	IoT³ TBR hybrid product	short windows: 3-bit state; daily/event totals: raw boundary	533	0.075	—	B=3 phase code does not anchor unresolved event-start/end residuals; same accumulation floor as the wired version of the same hardware.
1T	TBR MeteoRain 533 Classic	6.36	3.12	12.73	6.36	2.12	1.06	0.265	0.075	pulse-output TBR	raw pulse	533	0.075	—	Wired pulse output; tied with the IoT³ version of the same hardware at this horizon.
3	TBR Précis Mécanique 3039/1 dynamic-bucket gauge 1000 cm² 0.1 mm	8.22	4.10	16.43	8.22	2.74	1.37	0.342	0.1	pulse-output TBR	raw pulse	1000	0.1	—	Large 1000 cm² collector lowers the drop-count floor. The dynamic-bucket mechanism is modeled here as a pulse-output TBR because the ranking uses public resolution and collector area, not a vendor-specific dynamic correction.
4	TBR KISTERS/HyQuest TB6 0.1 mm special catch	8.293	4.114	16.59	8.293	2.764	1.382	0.3455	0.1	WMO / public exact TBR row	straight-through raw pulse; no siphon	628.3	0.1	—	TB6 special-catch 0.1 mm row; straight-through design, no siphon-storage term.
5T	TBR Meteoservis MR3H-FC / MR3H 500 cm² 0.1 mm	8.367	4.133	16.73	8.367	2.789	1.395	0.3486	0.1	WMO / public exact TBR row	raw pulse	500	0.1	—	Meteoservis MR3H-FC/MR3H 500 cm² / 0.1 mm row.
5T	WMO AP23 / PAAR 500 cm² 0.1 mm	8.367	4.133	16.73	8.367	2.789	1.395	0.3486	0.1	WMO historical exact-model TBR row	raw pulse	500	0.1	—	WMO/historical 500 cm² / 0.1 mm class; exact-model history, not a current product recommendation.
7	TBR Texas/Campbell TR-525M / TE525MM 245 mm 0.1 mm	8.39	4.14	16.79	8.39	2.80	1.40	0.35	0.1	pulse-output TBR	raw pulse	471.4	0.1	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
8T	IoT³ MeteoRain IoT³ 400 Aero (gen3)	8.48	4.16	16.97	8.48	2.83	1.41	0.353	0.0125 / 0.100	IoT³ TBR hybrid product	short windows: 3-bit state; daily/event totals: raw boundary	400	0.1	—	B=3 phase code does not anchor unresolved event-start/end residuals; same accumulation floor as the wired version of the same hardware.
8T	TBR CAE PG4i 400 cm² 0.1 mm	8.48	4.16	16.97	8.48	2.83	1.41	0.353	0.1	pulse-output TBR	raw pulse	400	0.1	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
8T	TBR Casella TBRG 400 cm² 0.1 mm	8.48	4.16	16.97	8.48	2.83	1.41	0.353	0.1	pulse-output TBR	raw pulse	400	0.1	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
8T	TBR MeteoRain 400 Aero	8.48	4.16	16.97	8.48	2.83	1.41	0.353	0.1	pulse-output TBR	raw pulse	400	0.1	—	Wired pulse output; tied with the IoT³ version of the same hardware at this horizon.
12T	TBR EML / In-Situ / Campbell ARG314 314 cm² 0.1 mm	8.69	4.21	17.38	8.69	2.90	1.45	0.362	0.1	pulse-output TBR	raw pulse	314	0.1	—	Aerodynamic 314 cm² tipping-bucket class; no siphon storage modeled. Same analytic class as 200 mm diameter / 0.1 mm gauges.
12T	TBR Honde / Renke 200 mm diameter 0.1 mm class	8.69	4.21	17.37	8.69	2.90	1.45	0.362	0.1	pulse-output TBR	raw pulse	314.2	0.1	—	Grouped 200 mm diameter low-cost/OEM products with published 0.1 mm configurations. Ranking is based only on public diameter and pulse resolution; field calibration and build quality are not scored.
12T	TBR Texas TR-525-W2 200 mm 0.1 mm	8.69	4.21	17.37	8.69	2.90	1.45	0.362	0.1	pulse-output TBR	raw pulse	314.2	0.1	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
15T	TBR Lambrecht 15189 / LB-15188 / 1518H3 0.1 mm	9.51	4.41	19.02	9.51	3.17	1.58	0.396	0.1	pulse-output TBR	raw pulse	200	0.1	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
15T	TBR MicroStep/Meteoservis MR2 200 cm² 0.1 mm option	9.51	4.41	19.02	9.51	3.17	1.58	0.396	0.1	pulse-output TBR	raw pulse	200	0.1	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
15T	TBR Thies PT 5.4032.35.008 200 cm² 0.1 mm	9.51	4.407	19.02	9.51	3.17	1.585	0.3963	0.1	WMO / public exact TBR row	raw pulse	200	0.1	—	Thies PT 200 cm² / 0.1 mm exact row.
18T	Historical Theodor Friedrichs 7011/7013 Hellmann recording rain gauge	10.00	5.00	20.00	10.00	3.33	1.67	0.417	0.1	historical float/siphon recording reference	200 cm² Hellmann recorder; 0.1 mm chart resolution; 10 mm siphon reset	200	—	—	Classic Hellmann recording rain gauge with 200 cm² orifice, 0.1 mm chart resolution, and 10 mm siphon reset; added as historical record/reference gauge.
18T	Weighing Lambrecht rain[e] / rain[e]LP / rain[e]314 / rain[e]400 / rain[e]H3 public amount-total	10.00	5.00	20.00	10.00	3.33	1.67	0.417	—	weighing public envelope	public fixed floor	—	—	—	Weighing public envelope: ±0.1 mm or ±1% accuracy floor, whichever is larger.
18T	Weighing OTT Pluvio² L Accu NRT / Accu total NRT	10.00	5.00	20.00	10.00	3.33	1.67	0.417	—	weighing public envelope	NRT amount product	—	—	—	Weighing public envelope: ±0.1 mm or ±1% accuracy floor, whichever is larger.
18T	Weighing OTT Pluvio² S Accu NRT / Accu total NRT	10.00	5.00	20.00	10.00	3.33	1.67	0.417	—	weighing public envelope	NRT amount product	—	—	—	Weighing public envelope: ±0.1 mm or ±1% accuracy floor, whichever is larger.
22T	TBR CAE PMB2 / PMB2/R 1000 cm² 0.2 mm	16.35	8.17	32.71	16.35	5.45	2.73	0.681	0.2	pulse-output TBR	raw pulse; correction algorithm not modelled	1000	0.2	—	1000 cm² / 0.2 mm tipping-bucket row. The public datasheet describes a compensation algorithm; this transparent table does not apply unpublished or product-specific correction details.
22T	TBR ETG R102 1000 cm² 0.2 mm	16.35	8.17	32.71	16.35	5.45	2.73	0.681	0.2	pulse-output TBR	raw pulse; correction algorithm not modelled	1000	0.2	—	1000 cm² / 0.2 mm tipping-bucket row with published correction algorithm. Ranked here from collector area and tip depth only so it remains comparable with other public-datasheet rows.
22T	WMO MTX PP040 1000 cm² 0.2 mm	16.35	8.171	32.71	16.35	5.452	2.726	0.6815	0.2	WMO historical exact-model TBR row	raw pulse	1000	0.2	—	1000 cm² / 0.2 mm class; retain range-gate caution from WMO validation layer.
22T	WMO R01 3070 / Précis-Mécanique 1000 cm² 0.2 mm	16.35	8.171	32.71	16.35	5.452	2.726	0.6815	0.2	WMO historical exact-model TBR row	raw pulse	1000	0.2	—	Distinct from the Précis 3039/1 1000 cm² / 0.1 mm row; WMO/historical 0.2 mm model.
22T	WMO SIAP UM7525 / T-PLUV UM7525/I 1000 cm² 0.2 mm	16.35	8.171	32.71	16.35	5.452	2.726	0.6815	0.2	WMO historical exact-model TBR row	raw pulse	1000	0.2	—	1000 cm² / 0.2 mm WMO/historical class.
27	TBR Vaisala QMR102 / EML ARG100 / Campbell ARG100 500 cm² 0.2 mm	16.43	8.19	32.86	16.43	5.48	2.74	0.685	0.2	pulse-output TBR	raw pulse	500	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
28	TBR Casella TBRG / CEL 100000E 400 cm² 0.2 mm	16.49	8.20	32.98	16.49	5.50	2.75	0.687	0.2	pulse-output TBR	raw pulse	400	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
29T	TBR FTS/AEM RG-T 0.2 mm option	16.57	8.225	33.14	16.57	5.523	2.762	0.6904	0.2	WMO / public exact TBR row	raw pulse	324.3	0.2	—	FTS/AEM RG-T optional metric row; same analytical class as 8 in / 324 cm² 0.2 mm gauges.
29T	TBR LSI Lastem DQA031 324 cm² 0.2 mm	16.57	8.225	33.14	16.57	5.523	2.762	0.6904	0.2	WMO / public exact TBR row	raw pulse	324.3	0.2	—	324 cm² / 0.2 mm exact row.
29T	TBR Met One 370D 324 cm² 0.2 mm	16.57	8.22	33.14	16.57	5.52	2.76	0.69	0.2	pulse-output TBR	raw pulse	324	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
29T	TBR RainWise wireless metric 8 in 0.2 mm	16.57	8.22	33.14	16.57	5.52	2.76	0.69	0.2	pulse-output TBR	raw pulse	324.3	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
29T	TBR Texas TR-525USW 8 in 0.2 mm	16.57	8.22	33.14	16.57	5.52	2.76	0.69	0.2	pulse-output TBR	raw pulse	324.3	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
34T	TBR EML / In-Situ / Campbell ARG314 314 cm² 0.2 mm	16.59	8.23	33.17	16.59	5.53	2.76	0.691	0.2	pulse-output TBR	raw pulse	314	0.2	—	Aerodynamic 314 cm² tipping-bucket class; standard 0.2 mm metric configuration.
34T	TBR KISTERS/HyQuest TB6 0.2 mm	16.59	8.229	33.17	16.59	5.528	2.764	0.691	0.2	WMO / public exact TBR row	straight-through raw pulse; no siphon	314.2	0.2	—	TB6 standard 0.2 mm row; no siphon-storage term.
34T	TBR Rika / Honde / Renke 200 mm diameter 0.2 mm class	16.59	8.23	33.17	16.59	5.53	2.76	0.691	0.2	pulse-output TBR	raw pulse	314.2	0.2	—	Grouped 200 mm diameter / 0.2 mm pulse-output class. Many products in this class share the same analytical floor; manufacturer envelope and calibration remain separate.
34T	TBR Texas TR-525-W2 200 mm 0.2 mm	16.59	8.23	33.18	16.59	5.53	2.77	0.691	0.2	pulse-output TBR	raw pulse	314.2	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
38	TBR Davis 6466/6466M AeroCone 214 cm² 0.2 mm	16.88	8.30	33.76	16.88	5.63	2.81	0.703	0.2	pulse-output TBR	raw pulse	214	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
39	TBR METER ECRN-100 16 cm collector 0.2 mm	16.96	8.32	33.92	16.96	5.65	2.83	0.707	0.2	pulse-output TBR	raw pulse	201.1	0.2	—	Double-spoon pulse gauge with 16 cm collector diameter and 0.2 mm/tip. Its analytical floor is nearly the same as the 200 cm² / 0.2 mm class.
40T	IoT³ MeteoRain IoT³ 200 Pro 0.2 mm (gen3)	16.97	8.32	33.93	16.97	5.66	2.83	0.707	0.0250 / 0.200	IoT³ TBR hybrid product	short windows: 3-bit state; daily/event totals: raw boundary	200	0.2	—	B=3 phase code does not anchor unresolved event-start/end residuals; same accumulation floor as the wired version of the same hardware.
40T	TBR Lambrecht 15189 0.2 mm	16.97	8.32	33.94	16.97	5.66	2.83	0.707	0.2	pulse-output TBR	raw pulse	200	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
40T	TBR MeteoRain 200 Pro 0.2 mm	16.97	8.32	33.94	16.97	5.66	2.83	0.707	0.2	pulse-output TBR	raw pulse	200	0.2	—	Wired pulse output; tied with the IoT³ version of the same hardware at this horizon.
40T	TBR MicroStep/Meteoservis MR2 200 cm² 0.2 mm	16.97	8.32	33.94	16.97	5.66	2.83	0.707	0.2	pulse-output TBR	raw pulse	200	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
40T	TBR Seven Sensor Solutions 3S-RG 0.2 mm — no siphon	16.97	8.32	33.94	16.97	5.66	2.83	0.707	0.2	pulse-output TBR	raw pulse	200	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
40T	TBR Vaisala QMR101 / Pronamic Professional 0.2 mm	16.97	8.32	33.94	16.97	5.66	2.83	0.707	0.2	pulse-output TBR	raw pulse	200	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
46	TBR Onset HOBO RG3-M 15.39 cm 0.2 mm	17.07	8.35	34.14	17.07	5.69	2.85	0.711	0.2	pulse-output TBR	raw pulse	186	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
47	Siphon KISTERS/HyQuest TB3/TB4/CS700 0.1 mm — siphon Vs=12 mL	17.73	8.83	35.46	17.73	5.91	2.96	0.739	0.1	siphon TBR	raw pulse + siphon	628.3	0.1	12	Bucket plus integrated siphon storage; γ_s = 1 conservative siphon residual added in quadrature.
48	Siphon Observator / RIMCO RIM-7499 siphon 0.2 mm	18.50	9.19	37.00	18.50	6.17	3.08	0.771	0.2	siphon TBR	raw pulse + siphon	323.7	0.2	3.2	Siphon-controlled 203 mm tipping-bucket gauge. Siphon storage is estimated as half of the bucket volume for the configured tip depth and included with γs = 1 as a conservative unresolved storage term.
49	TBR EML ARG100 optional 0.25 mm	20.49	10.23	40.98	20.49	6.83	3.41	0.854	0.25	pulse-output TBR	raw pulse	500	0.25	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
50T	TBR AEM/FTS 2408 8 in 0.01 in	20.93	10.42	41.86	20.93	6.98	3.49	0.872	0.254	pulse-output TBR	raw pulse	324.3	0.254	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
50T	TBR FTS/AEM RG-T 0.01 in / 0.254 mm	20.93	10.42	41.85	20.93	6.976	3.488	0.872	0.254	WMO / public exact TBR row	raw pulse	324.3	0.254	—	FTS/AEM RG-T imperial row; same analytical class as 8 in / 0.01 in gauges.
50T	TBR RainWise Rainew 8 in 0.01 in	20.93	10.42	41.86	20.93	6.98	3.49	0.872	0.254	pulse-output TBR	raw pulse	324.3	0.254	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
50T	TBR Texas/Campbell TR-525WS / TE525WS 8 in 0.01 in	20.93	10.42	41.86	20.93	6.98	3.49	0.872	0.254	pulse-output TBR	raw pulse	324.3	0.254	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
50T	TBR WaterLOG / Design Analysis H-340SDI 8 in 0.01 in	20.93	10.42	41.85	20.93	6.976	3.488	0.872	0.254	WMO / public exact TBR row	raw pulse	324.3	0.254	—	8 in / 0.01 in WaterLOG/Design Analysis row.
55	TBR KISTERS/HyQuest TB6 0.01 in / 0.254 mm	20.94	10.42	41.88	20.94	6.98	3.49	0.8725	0.254	WMO / public exact TBR row	straight-through raw pulse; no siphon	314.2	0.254	—	TB6 0.01 in row; no siphon-storage term.
56	TBR Davis 6466/6466M AeroCone / Rain Collector II 7852 214 cm² 0.01 in	21.17	10.48	42.34	21.17	7.06	3.53	0.882	0.254	pulse-output TBR	raw pulse	214	0.254	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
57T	IoT³ MeteoRain IoT³ 200 Pro 0.254 mm / 0.01 in (gen3)	21.24	10.49	42.47	21.24	7.08	3.54	0.885	0.0318 / 0.254	IoT³ TBR hybrid product	short windows: 3-bit state; daily/event totals: raw boundary	200	0.254	—	B=3 phase code does not anchor unresolved event-start/end residuals; same accumulation floor as the wired version of the same hardware.
57T	TBR MeteoRain 200 Pro 0.254 mm / 0.01 in	21.24	10.49	42.48	21.24	7.08	3.54	0.885	0.254	pulse-output TBR	raw pulse	200	0.254	—	Wired pulse output; tied with the IoT³ version of the same hardware at this horizon.
59	TBR Onset HOBO RG3 15.39 cm 0.01 in	21.32	10.51	42.64	21.32	7.11	3.55	0.888	0.254	pulse-output TBR	raw pulse	186	0.254	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
60	TBR Texas/Campbell TR-525 / TE525 6 in 0.01 in	21.34	10.52	42.68	21.34	7.11	3.56	0.889	0.254	pulse-output TBR	raw pulse	182.4	0.254	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
61	Siphon Observator / RIMCO RIM-7499 siphon 0.25 mm	23.01	11.46	46.03	23.01	7.67	3.84	0.959	0.25	siphon TBR	raw pulse + siphon	323.7	0.2	4.0	Siphon-controlled 203 mm tipping-bucket gauge. Siphon storage is estimated as half of the bucket volume for the configured tip depth and included with γs = 1 as a conservative unresolved storage term.
62	Siphon Geolux RG400 0.1 mm — siphon Vs≈16 mL, 4 mL/tip	33.98	16.91	67.96	33.98	11.33	5.66	1.42	0.1	siphon TBR	raw pulse + siphon	400	0.1	16	Bucket plus integrated siphon storage; γ_s = 1 conservative siphon residual added in quadrature.
63	Siphon KISTERS/HyQuest TB3/TB4/CS700 0.2 mm — siphon Vs=12 mL	35.45	17.66	70.90	35.45	11.82	5.91	1.48	0.2	siphon TBR	raw pulse + siphon	314.2	0.2	12	Bucket plus integrated siphon storage; γ_s = 1 conservative siphon residual added in quadrature.
64	Siphon Hydrological Services TB-3 0.2 mm siphon — exact WMO row, s = 0.4 mm	36.77	18.32	73.54	36.77	12.26	6.128	1.532	0.4472	WMO historical exact siphon TBR row	raw pulse + siphon	314.2	0.2	12.57 s=0.4 mm	TB-3 exact WMO/historical row uses the published siphon rainfall-depth term s = 0.4 mm.
65	Siphon Geolux RG200 0.2 mm — siphon Vs≈8 mL, 4 mL/tip	37.15	18.41	74.30	37.15	12.38	6.19	1.55	0.2	siphon TBR	raw pulse + siphon	200	0.2	8	Bucket plus integrated siphon storage; γ_s = 1 conservative siphon residual added in quadrature.
66	Siphon KISTERS/HyQuest TB3/TB4 / Campbell CS700/CS700H 0.01 in — siphon Vs=12 mL	37.65	18.78	75.30	37.65	12.55	6.27	1.57	0.254	siphon TBR	raw pulse + siphon	314.2	0.254	12	Bucket plus integrated siphon storage; γ_s = 1 conservative siphon residual added in quadrature.
67	TBR Casella TBRG 400 cm² 0.5 mm	40.89	20.43	81.78	40.89	13.63	6.82	1.70	0.5	pulse-output TBR	raw pulse	400	0.5	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
68T	TBR EML / In-Situ ARG314 314 cm² 0.5 mm option	40.93	20.44	81.85	40.93	13.64	6.82	1.71	0.5	pulse-output TBR	raw pulse	314	0.5	—	Optional coarse-resolution ARG314 configuration; included as a technical comparison because 0.5 mm tips are less suitable for short-window precision.
68T	TBR KISTERS/HyQuest TB6 0.5 mm	40.93	20.44	81.85	40.93	13.64	6.821	1.705	0.5	Technical low-resolution TBR row	straight-through raw pulse; no siphon	314.2	0.5	—	TB6 coarse 0.5 mm option retained as a technical comparison row.
68T	TBR Rika / Honde / Renke / Tamaya 200 mm diameter 0.5 mm class	40.93	20.44	81.85	40.93	13.64	6.82	1.71	0.5	pulse-output TBR	raw pulse	314.2	0.5	—	Grouped 200 mm diameter / 0.5 mm pulse-output class. The coarse tip depth dominates the analytical floor.
68T	WMO India Met Dept. TBRG Mk2 314 cm² 0.5 mm	40.93	20.44	81.85	40.93	13.64	6.821	1.705	0.5	WMO historical technical TBR row	raw pulse	314.2	0.5	—	WMO historical 314 cm² / 0.5 mm technical row.
72	TBR MicroStep/Meteoservis MR2 200 cm² 0.5 mm option	41.08	20.48	82.16	41.08	13.69	6.85	1.71	0.5	pulse-output TBR	raw pulse	200	0.5	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
73	Siphon Observator / RIMCO RIM-7499 siphon 0.5 mm	45.74	22.85	91.48	45.74	15.25	7.62	1.91	0.5	siphon TBR	raw pulse + siphon	323.7	0.5	8.1	Siphon-controlled 203 mm tipping-bucket gauge. Siphon storage is estimated as half of the bucket volume for the configured tip depth and included with γs = 1 as a conservative unresolved storage term.
74	Siphon KISTERS/HyQuest TB3/TB4 0.5 mm siphon Vs=12 mL	51.47	25.71	102.95	51.47	17.16	8.579	2.145	0.6292	Technical low-resolution siphon TBR row	raw pulse + siphon	314.2	0.5	12	Coarse TB3/TB4 0.5 mm siphon row with Vs = 12 mL retained for technical completeness.
75T	TBR KISTERS/HyQuest TB6 1.0 mm	81.70	40.84	163.40	81.70	27.23	13.62	3.404	1	Technical low-resolution TBR row	straight-through raw pulse; no siphon	314.2	1	—	TB6 coarse 1.0 mm option retained as a low-resolution technical comparison row.
75T	WMO Yokogawa Denshi Kiki WMB01 314 cm² 1.0 mm	81.70	40.84	163.40	81.70	27.23	13.62	3.404	1	WMO historical technical TBR row	raw pulse	314.2	1	—	WMO historical 314 cm² / 1.0 mm low-resolution technical row.
77	Siphon KISTERS/HyQuest TB3/TB4 1.0 mm siphon Vs=12 mL	87.45	43.71	174.91	87.45	29.15	14.58	3.644	1.07	Technical low-resolution siphon TBR row	raw pulse + siphon	314.2	1	12	Coarse TB3/TB4 1.0 mm siphon row with Vs = 12 mL retained for technical completeness.
—	Weighing Lambrecht rain[e]one Modbus public amount-total	—	5.00	—	—	—	—	—	—	weighing public envelope	public fixed floor	—	—	—	Weighing public envelope: ±0.1 mm or ±1% accuracy floor, whichever is larger.
—	Weighing OTT Pluvio² L Intensity RT	—	—	—	—	—	—	—	—	weighing public envelope	RT 1-min intensity	—	—	—	Weighing public envelope: ±0.1 mm or ±1% accuracy floor, whichever is larger.
—	Weighing OTT Pluvio² S Intensity RT	—	—	—	—	—	—	—	—	weighing public envelope	RT 1-min intensity	—	—	—	Weighing public envelope: ±0.1 mm or ±1% accuracy floor, whichever is larger.

Within-category rankings

The same 46 products grouped by gauge family, so within-class comparisons are immediate. The within-class rank in each sub-table below is computed within that family only.

Column legend (applies to overall and per-category tables)

In the overall table above, sorted by required depth at 1%. In the per-category tables below, sorted by required depth at 1% (lower is better). The within-class rank shows where each product sits within its own family. Δ_res is the unresolved leftover-water resolution (mm). A is collector area (cm²). d / d_eq is tip depth or equivalent self-emptying event depth (mm). V_s is siphon storage volume (mL). The 1% @ 30 min through @ 24 h columns convert the 1% required depth into average rainfall rate (mm/h) over that horizon; this lets a planner check whether realistic rainfall intensity at the deployment site will reach the target threshold within the chosen reporting window. Columns shaded grey are technical audit data; the main accuracy comparison is in the leftmost numerical columns.

Tipping bucket gauges (raw pulse, IoT³, and WMO exact-model rows) — 62 rows

For accumulation totals, raw-pulse and IoT³ phase-aware tipping buckets share the same floor on the same hardware because B=3 cannot anchor unresolved event-start and event-end residuals. Within this category, the smallest tip depth (highest resolution) and largest collector area win. The IoT³ phase-aware advantage is in the intensity ranking, not here.

Table navigation: scroll left and right inside the table box to see all columns. The rank and gauge columns remain pinned; notes and technical evidence columns sit farther to the right.

In-class rank	Gauge / output product	P_min at 1% (mm)	P_min at 2% (mm)	1% @30 min (mm/h)	1% @1 h (mm/h)	1% @3 h (mm/h)	1% @6 h (mm/h)	1% @24 h (mm/h)	Δ_res (mm)	Evidence layer	State detail	A (cm²)	d / d_eq (mm)	V_s (mL)	Why it ranks here
1T	IoT³ MeteoRain IoT³ 533 Classic (gen3)	6.36	3.12	12.73	6.36	2.12	1.06	0.265	0.0094 / 0.075	IoT³ TBR hybrid product	short windows: 3-bit state; daily/event totals: raw boundary	533	0.075	—	B=3 phase code does not anchor unresolved event-start/end residuals; same accumulation floor as the wired version of the same hardware.
1T	TBR MeteoRain 533 Classic	6.36	3.12	12.73	6.36	2.12	1.06	0.265	0.075	pulse-output TBR	raw pulse	533	0.075	—	Wired pulse output; tied with the IoT³ version of the same hardware at this horizon.
3	TBR Précis Mécanique 3039/1 dynamic-bucket gauge 1000 cm² 0.1 mm	8.22	4.10	16.43	8.22	2.74	1.37	0.342	0.1	pulse-output TBR	raw pulse	1000	0.1	—	Large 1000 cm² collector lowers the drop-count floor. The dynamic-bucket mechanism is modeled here as a pulse-output TBR because the ranking uses public resolution and collector area, not a vendor-specific dynamic correction.
4	TBR KISTERS/HyQuest TB6 0.1 mm special catch	8.293	4.114	16.59	8.293	2.764	1.382	0.3455	0.1	WMO / public exact TBR row	straight-through raw pulse; no siphon	628.3	0.1	—	TB6 special-catch 0.1 mm row; straight-through design, no siphon-storage term.
5T	TBR Meteoservis MR3H-FC / MR3H 500 cm² 0.1 mm	8.367	4.133	16.73	8.367	2.789	1.395	0.3486	0.1	WMO / public exact TBR row	raw pulse	500	0.1	—	Meteoservis MR3H-FC/MR3H 500 cm² / 0.1 mm row.
5T	WMO AP23 / PAAR 500 cm² 0.1 mm	8.367	4.133	16.73	8.367	2.789	1.395	0.3486	0.1	WMO historical exact-model TBR row	raw pulse	500	0.1	—	WMO/historical 500 cm² / 0.1 mm class; exact-model history, not a current product recommendation.
7	TBR Texas/Campbell TR-525M / TE525MM 245 mm 0.1 mm	8.39	4.14	16.79	8.39	2.80	1.40	0.35	0.1	pulse-output TBR	raw pulse	471.4	0.1	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
8T	IoT³ MeteoRain IoT³ 400 Aero (gen3)	8.48	4.16	16.97	8.48	2.83	1.41	0.353	0.0125 / 0.100	IoT³ TBR hybrid product	short windows: 3-bit state; daily/event totals: raw boundary	400	0.1	—	B=3 phase code does not anchor unresolved event-start/end residuals; same accumulation floor as the wired version of the same hardware.
8T	TBR CAE PG4i 400 cm² 0.1 mm	8.48	4.16	16.97	8.48	2.83	1.41	0.353	0.1	pulse-output TBR	raw pulse	400	0.1	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
8T	TBR Casella TBRG 400 cm² 0.1 mm	8.48	4.16	16.97	8.48	2.83	1.41	0.353	0.1	pulse-output TBR	raw pulse	400	0.1	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
8T	TBR MeteoRain 400 Aero	8.48	4.16	16.97	8.48	2.83	1.41	0.353	0.1	pulse-output TBR	raw pulse	400	0.1	—	Wired pulse output; tied with the IoT³ version of the same hardware at this horizon.
12T	TBR EML / In-Situ / Campbell ARG314 314 cm² 0.1 mm	8.69	4.21	17.38	8.69	2.90	1.45	0.362	0.1	pulse-output TBR	raw pulse	314	0.1	—	Aerodynamic 314 cm² tipping-bucket class; no siphon storage modeled. Same analytic class as 200 mm diameter / 0.1 mm gauges.
12T	TBR Honde / Renke 200 mm diameter 0.1 mm class	8.69	4.21	17.37	8.69	2.90	1.45	0.362	0.1	pulse-output TBR	raw pulse	314.2	0.1	—	Grouped 200 mm diameter low-cost/OEM products with published 0.1 mm configurations. Ranking is based only on public diameter and pulse resolution; field calibration and build quality are not scored.
12T	TBR Texas TR-525-W2 200 mm 0.1 mm	8.69	4.21	17.37	8.69	2.90	1.45	0.362	0.1	pulse-output TBR	raw pulse	314.2	0.1	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
15T	TBR Lambrecht 15189 / LB-15188 / 1518H3 0.1 mm	9.51	4.41	19.02	9.51	3.17	1.58	0.396	0.1	pulse-output TBR	raw pulse	200	0.1	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
15T	TBR MicroStep/Meteoservis MR2 200 cm² 0.1 mm option	9.51	4.41	19.02	9.51	3.17	1.58	0.396	0.1	pulse-output TBR	raw pulse	200	0.1	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
15T	TBR Thies PT 5.4032.35.008 200 cm² 0.1 mm	9.51	4.407	19.02	9.51	3.17	1.585	0.3963	0.1	WMO / public exact TBR row	raw pulse	200	0.1	—	Thies PT 200 cm² / 0.1 mm exact row.
18T	TBR CAE PMB2 / PMB2/R 1000 cm² 0.2 mm	16.35	8.17	32.71	16.35	5.45	2.73	0.681	0.2	pulse-output TBR	raw pulse; correction algorithm not modelled	1000	0.2	—	1000 cm² / 0.2 mm tipping-bucket row. The public datasheet describes a compensation algorithm; this transparent table does not apply unpublished or product-specific correction details.
18T	TBR ETG R102 1000 cm² 0.2 mm	16.35	8.17	32.71	16.35	5.45	2.73	0.681	0.2	pulse-output TBR	raw pulse; correction algorithm not modelled	1000	0.2	—	1000 cm² / 0.2 mm tipping-bucket row with published correction algorithm. Ranked here from collector area and tip depth only so it remains comparable with other public-datasheet rows.
18T	WMO MTX PP040 1000 cm² 0.2 mm	16.35	8.171	32.71	16.35	5.452	2.726	0.6815	0.2	WMO historical exact-model TBR row	raw pulse	1000	0.2	—	1000 cm² / 0.2 mm class; retain range-gate caution from WMO validation layer.
18T	WMO R01 3070 / Précis-Mécanique 1000 cm² 0.2 mm	16.35	8.171	32.71	16.35	5.452	2.726	0.6815	0.2	WMO historical exact-model TBR row	raw pulse	1000	0.2	—	Distinct from the Précis 3039/1 1000 cm² / 0.1 mm row; WMO/historical 0.2 mm model.
18T	WMO SIAP UM7525 / T-PLUV UM7525/I 1000 cm² 0.2 mm	16.35	8.171	32.71	16.35	5.452	2.726	0.6815	0.2	WMO historical exact-model TBR row	raw pulse	1000	0.2	—	1000 cm² / 0.2 mm WMO/historical class.
23	TBR Vaisala QMR102 / EML ARG100 / Campbell ARG100 500 cm² 0.2 mm	16.43	8.19	32.86	16.43	5.48	2.74	0.685	0.2	pulse-output TBR	raw pulse	500	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
24	TBR Casella TBRG / CEL 100000E 400 cm² 0.2 mm	16.49	8.20	32.98	16.49	5.50	2.75	0.687	0.2	pulse-output TBR	raw pulse	400	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
25T	TBR FTS/AEM RG-T 0.2 mm option	16.57	8.225	33.14	16.57	5.523	2.762	0.6904	0.2	WMO / public exact TBR row	raw pulse	324.3	0.2	—	FTS/AEM RG-T optional metric row; same analytical class as 8 in / 324 cm² 0.2 mm gauges.
25T	TBR LSI Lastem DQA031 324 cm² 0.2 mm	16.57	8.225	33.14	16.57	5.523	2.762	0.6904	0.2	WMO / public exact TBR row	raw pulse	324.3	0.2	—	324 cm² / 0.2 mm exact row.
25T	TBR Met One 370D 324 cm² 0.2 mm	16.57	8.22	33.14	16.57	5.52	2.76	0.69	0.2	pulse-output TBR	raw pulse	324	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
25T	TBR RainWise wireless metric 8 in 0.2 mm	16.57	8.22	33.14	16.57	5.52	2.76	0.69	0.2	pulse-output TBR	raw pulse	324.3	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
25T	TBR Texas TR-525USW 8 in 0.2 mm	16.57	8.22	33.14	16.57	5.52	2.76	0.69	0.2	pulse-output TBR	raw pulse	324.3	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
30T	TBR EML / In-Situ / Campbell ARG314 314 cm² 0.2 mm	16.59	8.23	33.17	16.59	5.53	2.76	0.691	0.2	pulse-output TBR	raw pulse	314	0.2	—	Aerodynamic 314 cm² tipping-bucket class; standard 0.2 mm metric configuration.
30T	TBR KISTERS/HyQuest TB6 0.2 mm	16.59	8.229	33.17	16.59	5.528	2.764	0.691	0.2	WMO / public exact TBR row	straight-through raw pulse; no siphon	314.2	0.2	—	TB6 standard 0.2 mm row; no siphon-storage term.
30T	TBR Rika / Honde / Renke 200 mm diameter 0.2 mm class	16.59	8.23	33.17	16.59	5.53	2.76	0.691	0.2	pulse-output TBR	raw pulse	314.2	0.2	—	Grouped 200 mm diameter / 0.2 mm pulse-output class. Many products in this class share the same analytical floor; manufacturer envelope and calibration remain separate.
30T	TBR Texas TR-525-W2 200 mm 0.2 mm	16.59	8.23	33.18	16.59	5.53	2.77	0.691	0.2	pulse-output TBR	raw pulse	314.2	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
34	TBR Davis 6466/6466M AeroCone 214 cm² 0.2 mm	16.88	8.30	33.76	16.88	5.63	2.81	0.703	0.2	pulse-output TBR	raw pulse	214	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
35	TBR METER ECRN-100 16 cm collector 0.2 mm	16.96	8.32	33.92	16.96	5.65	2.83	0.707	0.2	pulse-output TBR	raw pulse	201.1	0.2	—	Double-spoon pulse gauge with 16 cm collector diameter and 0.2 mm/tip. Its analytical floor is nearly the same as the 200 cm² / 0.2 mm class.
36T	IoT³ MeteoRain IoT³ 200 Pro 0.2 mm (gen3)	16.97	8.32	33.93	16.97	5.66	2.83	0.707	0.0250 / 0.200	IoT³ TBR hybrid product	short windows: 3-bit state; daily/event totals: raw boundary	200	0.2	—	B=3 phase code does not anchor unresolved event-start/end residuals; same accumulation floor as the wired version of the same hardware.
36T	TBR Lambrecht 15189 0.2 mm	16.97	8.32	33.94	16.97	5.66	2.83	0.707	0.2	pulse-output TBR	raw pulse	200	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
36T	TBR MeteoRain 200 Pro 0.2 mm	16.97	8.32	33.94	16.97	5.66	2.83	0.707	0.2	pulse-output TBR	raw pulse	200	0.2	—	Wired pulse output; tied with the IoT³ version of the same hardware at this horizon.
36T	TBR MicroStep/Meteoservis MR2 200 cm² 0.2 mm	16.97	8.32	33.94	16.97	5.66	2.83	0.707	0.2	pulse-output TBR	raw pulse	200	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
36T	TBR Seven Sensor Solutions 3S-RG 0.2 mm — no siphon	16.97	8.32	33.94	16.97	5.66	2.83	0.707	0.2	pulse-output TBR	raw pulse	200	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
36T	TBR Vaisala QMR101 / Pronamic Professional 0.2 mm	16.97	8.32	33.94	16.97	5.66	2.83	0.707	0.2	pulse-output TBR	raw pulse	200	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
42	TBR Onset HOBO RG3-M 15.39 cm 0.2 mm	17.07	8.35	34.14	17.07	5.69	2.85	0.711	0.2	pulse-output TBR	raw pulse	186	0.2	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
43	TBR EML ARG100 optional 0.25 mm	20.49	10.23	40.98	20.49	6.83	3.41	0.854	0.25	pulse-output TBR	raw pulse	500	0.25	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
44T	TBR AEM/FTS 2408 8 in 0.01 in	20.93	10.42	41.86	20.93	6.98	3.49	0.872	0.254	pulse-output TBR	raw pulse	324.3	0.254	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
44T	TBR FTS/AEM RG-T 0.01 in / 0.254 mm	20.93	10.42	41.85	20.93	6.976	3.488	0.872	0.254	WMO / public exact TBR row	raw pulse	324.3	0.254	—	FTS/AEM RG-T imperial row; same analytical class as 8 in / 0.01 in gauges.
44T	TBR RainWise Rainew 8 in 0.01 in	20.93	10.42	41.86	20.93	6.98	3.49	0.872	0.254	pulse-output TBR	raw pulse	324.3	0.254	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
44T	TBR Texas/Campbell TR-525WS / TE525WS 8 in 0.01 in	20.93	10.42	41.86	20.93	6.98	3.49	0.872	0.254	pulse-output TBR	raw pulse	324.3	0.254	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
44T	TBR WaterLOG / Design Analysis H-340SDI 8 in 0.01 in	20.93	10.42	41.85	20.93	6.976	3.488	0.872	0.254	WMO / public exact TBR row	raw pulse	324.3	0.254	—	8 in / 0.01 in WaterLOG/Design Analysis row.
49	TBR KISTERS/HyQuest TB6 0.01 in / 0.254 mm	20.94	10.42	41.88	20.94	6.98	3.49	0.8725	0.254	WMO / public exact TBR row	straight-through raw pulse; no siphon	314.2	0.254	—	TB6 0.01 in row; no siphon-storage term.
50	TBR Davis 6466/6466M AeroCone / Rain Collector II 7852 214 cm² 0.01 in	21.17	10.48	42.34	21.17	7.06	3.53	0.882	0.254	pulse-output TBR	raw pulse	214	0.254	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
51T	IoT³ MeteoRain IoT³ 200 Pro 0.254 mm / 0.01 in (gen3)	21.24	10.49	42.47	21.24	7.08	3.54	0.885	0.0318 / 0.254	IoT³ TBR hybrid product	short windows: 3-bit state; daily/event totals: raw boundary	200	0.254	—	B=3 phase code does not anchor unresolved event-start/end residuals; same accumulation floor as the wired version of the same hardware.
51T	TBR MeteoRain 200 Pro 0.254 mm / 0.01 in	21.24	10.49	42.48	21.24	7.08	3.54	0.885	0.254	pulse-output TBR	raw pulse	200	0.254	—	Wired pulse output; tied with the IoT³ version of the same hardware at this horizon.
53	TBR Onset HOBO RG3 15.39 cm 0.01 in	21.32	10.51	42.64	21.32	7.11	3.55	0.888	0.254	pulse-output TBR	raw pulse	186	0.254	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
54	TBR Texas/Campbell TR-525 / TE525 6 in 0.01 in	21.34	10.52	42.68	21.34	7.11	3.56	0.889	0.254	pulse-output TBR	raw pulse	182.4	0.254	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
55	TBR Casella TBRG 400 cm² 0.5 mm	40.89	20.43	81.78	40.89	13.63	6.82	1.70	0.5	pulse-output TBR	raw pulse	400	0.5	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
56T	TBR EML / In-Situ ARG314 314 cm² 0.5 mm option	40.93	20.44	81.85	40.93	13.64	6.82	1.71	0.5	pulse-output TBR	raw pulse	314	0.5	—	Optional coarse-resolution ARG314 configuration; included as a technical comparison because 0.5 mm tips are less suitable for short-window precision.
56T	TBR KISTERS/HyQuest TB6 0.5 mm	40.93	20.44	81.85	40.93	13.64	6.821	1.705	0.5	Technical low-resolution TBR row	straight-through raw pulse; no siphon	314.2	0.5	—	TB6 coarse 0.5 mm option retained as a technical comparison row.
56T	TBR Rika / Honde / Renke / Tamaya 200 mm diameter 0.5 mm class	40.93	20.44	81.85	40.93	13.64	6.82	1.71	0.5	pulse-output TBR	raw pulse	314.2	0.5	—	Grouped 200 mm diameter / 0.5 mm pulse-output class. The coarse tip depth dominates the analytical floor.
56T	WMO India Met Dept. TBRG Mk2 314 cm² 0.5 mm	40.93	20.44	81.85	40.93	13.64	6.821	1.705	0.5	WMO historical technical TBR row	raw pulse	314.2	0.5	—	WMO historical 314 cm² / 0.5 mm technical row.
60	TBR MicroStep/Meteoservis MR2 200 cm² 0.5 mm option	41.08	20.48	82.16	41.08	13.69	6.85	1.71	0.5	pulse-output TBR	raw pulse	200	0.5	—	Pulse-output tipping bucket; ranked by collector area and tip depth.
61T	TBR KISTERS/HyQuest TB6 1.0 mm	81.70	40.84	163.40	81.70	27.23	13.62	3.404	1	Technical low-resolution TBR row	straight-through raw pulse; no siphon	314.2	1	—	TB6 coarse 1.0 mm option retained as a low-resolution technical comparison row.
61T	WMO Yokogawa Denshi Kiki WMB01 314 cm² 1.0 mm	81.70	40.84	163.40	81.70	27.23	13.62	3.404	1	WMO historical technical TBR row	raw pulse	314.2	1	—	WMO historical 314 cm² / 1.0 mm low-resolution technical row.

Siphon-equipped tipping bucket gauges — 11 rows

Siphon-equipped tipping buckets add an unresolved siphon-storage residual to the boundary uncertainty. The conservative γ_s = 1 assumption used in this table treats the full siphon residual as unresolved; a measured γ_s would shift these thresholds proportionally (see Appendix A2 sample calculation 3 and the γ_s sensitivity discussion below).

Table navigation: scroll left and right inside the table box to see all columns. The rank and gauge columns remain pinned; notes and technical evidence columns sit farther to the right.

In-class rank	Gauge / output product	P_min at 1% (mm)	P_min at 2% (mm)	1% @30 min (mm/h)	1% @1 h (mm/h)	1% @3 h (mm/h)	1% @6 h (mm/h)	1% @24 h (mm/h)	Δ_res (mm)	Evidence layer	State detail	A (cm²)	d / d_eq (mm)	V_s (mL)	Why it ranks here
1	Siphon KISTERS/HyQuest TB3/TB4/CS700 0.1 mm — siphon Vs=12 mL	17.73	8.83	35.46	17.73	5.91	2.96	0.739	0.1	siphon TBR	raw pulse + siphon	628.3	0.1	12	Bucket plus integrated siphon storage; γ_s = 1 conservative siphon residual added in quadrature.
2	Siphon Observator / RIMCO RIM-7499 siphon 0.2 mm	18.50	9.19	37.00	18.50	6.17	3.08	0.771	0.2	siphon TBR	raw pulse + siphon	323.7	0.2	3.2	Siphon-controlled 203 mm tipping-bucket gauge. Siphon storage is estimated as half of the bucket volume for the configured tip depth and included with γs = 1 as a conservative unresolved storage term.
3	Siphon Observator / RIMCO RIM-7499 siphon 0.25 mm	23.01	11.46	46.03	23.01	7.67	3.84	0.959	0.25	siphon TBR	raw pulse + siphon	323.7	0.2	4.0	Siphon-controlled 203 mm tipping-bucket gauge. Siphon storage is estimated as half of the bucket volume for the configured tip depth and included with γs = 1 as a conservative unresolved storage term.
4	Siphon Geolux RG400 0.1 mm — siphon Vs≈16 mL, 4 mL/tip	33.98	16.91	67.96	33.98	11.33	5.66	1.42	0.1	siphon TBR	raw pulse + siphon	400	0.1	16	Bucket plus integrated siphon storage; γ_s = 1 conservative siphon residual added in quadrature.
5	Siphon KISTERS/HyQuest TB3/TB4/CS700 0.2 mm — siphon Vs=12 mL	35.45	17.66	70.90	35.45	11.82	5.91	1.48	0.2	siphon TBR	raw pulse + siphon	314.2	0.2	12	Bucket plus integrated siphon storage; γ_s = 1 conservative siphon residual added in quadrature.
6	Siphon Hydrological Services TB-3 0.2 mm siphon — exact WMO row, s = 0.4 mm	36.77	18.32	73.54	36.77	12.26	6.128	1.532	0.4472	WMO historical exact siphon TBR row	raw pulse + siphon	314.2	0.2	12.57 s=0.4 mm	TB-3 exact WMO/historical row uses the published siphon rainfall-depth term s = 0.4 mm.
7	Siphon Geolux RG200 0.2 mm — siphon Vs≈8 mL, 4 mL/tip	37.15	18.41	74.30	37.15	12.38	6.19	1.55	0.2	siphon TBR	raw pulse + siphon	200	0.2	8	Bucket plus integrated siphon storage; γ_s = 1 conservative siphon residual added in quadrature.
8	Siphon KISTERS/HyQuest TB3/TB4 / Campbell CS700/CS700H 0.01 in — siphon Vs=12 mL	37.65	18.78	75.30	37.65	12.55	6.27	1.57	0.254	siphon TBR	raw pulse + siphon	314.2	0.254	12	Bucket plus integrated siphon storage; γ_s = 1 conservative siphon residual added in quadrature.
9	Siphon Observator / RIMCO RIM-7499 siphon 0.5 mm	45.74	22.85	91.48	45.74	15.25	7.62	1.91	0.5	siphon TBR	raw pulse + siphon	323.7	0.5	8.1	Siphon-controlled 203 mm tipping-bucket gauge. Siphon storage is estimated as half of the bucket volume for the configured tip depth and included with γs = 1 as a conservative unresolved storage term.
10	Siphon KISTERS/HyQuest TB3/TB4 0.5 mm siphon Vs=12 mL	51.47	25.71	102.95	51.47	17.16	8.579	2.145	0.6292	Technical low-resolution siphon TBR row	raw pulse + siphon	314.2	0.5	12	Coarse TB3/TB4 0.5 mm siphon row with Vs = 12 mL retained for technical completeness.
11	Siphon KISTERS/HyQuest TB3/TB4 1.0 mm siphon Vs=12 mL	87.45	43.71	174.91	87.45	29.15	14.58	3.644	1.07	Technical low-resolution siphon TBR row	raw pulse + siphon	314.2	1	12	Coarse TB3/TB4 1.0 mm siphon row with Vs = 12 mL retained for technical completeness.

Weighing, historical, and recording reference gauges — 7 rows

The public weighing envelope establishes a fixed amount floor of 0.1 mm or 1% (whichever is larger). For accumulation totals where the 5–10 minute NRT delay is acceptable, weighing gauges are competitive on the analytical floor and may also win on operational properties (no moving parts) that this ranking does not score.

Table navigation: scroll left and right inside the table box to see all columns. The rank and gauge columns remain pinned; notes and technical evidence columns sit farther to the right.

In-class rank	Gauge / output product	P_min at 1% (mm)	P_min at 2% (mm)	1% @30 min (mm/h)	1% @1 h (mm/h)	1% @3 h (mm/h)	1% @6 h (mm/h)	1% @24 h (mm/h)	Δ_res (mm)	Evidence layer	State detail	A (cm²)	d / d_eq (mm)	V_s (mL)	Why it ranks here
1T	Weighing Lambrecht rain[e] / rain[e]LP / rain[e]314 / rain[e]400 / rain[e]H3 public amount-total	10.00	5.00	20.00	10.00	3.33	1.67	0.417	—	weighing public envelope	public fixed floor	—	—	—	Weighing public envelope: ±0.1 mm or ±1% accuracy floor, whichever is larger.
1T	Weighing OTT Pluvio² L Accu NRT / Accu total NRT	10.00	5.00	20.00	10.00	3.33	1.67	0.417	—	weighing public envelope	NRT amount product	—	—	—	Weighing public envelope: ±0.1 mm or ±1% accuracy floor, whichever is larger.
1T	Weighing OTT Pluvio² S Accu NRT / Accu total NRT	10.00	5.00	20.00	10.00	3.33	1.67	0.417	—	weighing public envelope	NRT amount product	—	—	—	Weighing public envelope: ±0.1 mm or ±1% accuracy floor, whichever is larger.
1T	Historical Theodor Friedrichs 7011/7013 Hellmann recording rain gauge	10.00	5.00	20.00	10.00	3.33	1.67	0.417	0.1	historical float/siphon recording reference	200 cm² Hellmann recorder; 0.1 mm chart resolution; 10 mm siphon reset	200	—	—	Classic Hellmann recording rain gauge with 200 cm² orifice, 0.1 mm chart resolution, and 10 mm siphon reset; added as historical record/reference gauge.
N/R	Weighing Lambrecht rain[e]one Modbus public amount-total	—	5.00	—	—	—	—	—	—	weighing public envelope	public fixed floor	—	—	—	Weighing public envelope: ±0.1 mm or ±1% accuracy floor, whichever is larger.
N/R	Weighing OTT Pluvio² L Intensity RT	—	—	—	—	—	—	—	—	weighing public envelope	RT 1-min intensity	—	—	—	Weighing public envelope: ±0.1 mm or ±1% accuracy floor, whichever is larger.
N/R	Weighing OTT Pluvio² S Intensity RT	—	—	—	—	—	—	—	—	weighing public envelope	RT 1-min intensity	—	—	—	Weighing public envelope: ±0.1 mm or ±1% accuracy floor, whichever is larger.

Why MeteoRain IoT³ ties the wired version in this ranking

The IoT³ phase code helps when both ends of a reporting window are inside an active rainfall sequence. A daily or event total is different: the start and end usually occur in dry conditions, where the window is not bracketed by tips. The unresolved event-boundary residual remains, and the IoT³ version and the wired version of the same hardware share the same accumulation floor. The smallest-bucket product in each category wins on hardware (smaller bucket = more accurate per tip) — a fact about geometry, not telemetry, and not about brand.

Where weighing products compete

Dynamic response of weighing gauges

WMO laboratory and field intercomparison work supports the main caution used in this article: weighing gauges can be accurate under constant-flow laboratory conditions after stabilization, yet their 1-minute rainfall-intensity performance depends on acquisition-system response time and internal filtering. WMO reported significant delays in the sensing of rain-intensity time variation by weighing gauges and found that only one instrument met the WMO 1-minute rainfall-intensity requirement.

The WMO/JMA summary of the laboratory intercomparison describes the step-response test for weighing gauges: flow was switched from 0 to 200 mm/h and back to 0, then the output was observed until it stabilized, with possible delay evaluated at better than 1-minute resolution. Therefore, a weighing gauge is not ranked from digital resolution alone. It is ranked for dynamic intensity only when the public documentation identifies the output product, sampling interval, output delay, filtering behavior, and response to changing rainfall.

The OTT Pluvio² L/S Accu NRT amount product and the Lambrecht rain[e] amount-derived public envelope both publish a 0.1 mm or 1% accuracy floor. That works out to a 10 mm threshold at the 1% target — comparable to a 200 cm² 0.1 mm wired tipping bucket and ahead of the 0.2 mm tipping buckets and every siphon TBR variant in this table. For daily totals where the application can tolerate a 5–10 minute output delay, weighing products are competitive on the analytical floor and may also win on operational properties (no moving parts, less seasonal maintenance) that this ranking does not score. For sub-hourly intensity the picture changes; see the companion intensity ranking.

Unranked weighing-gauge note: MPS TRwS, Apogee Cloudburst, and Geonor T-200B

Unranked weighing references. Geonor T-200B, Apogee Cloudburst, and MPS/TRwS are legitimate weighing precipitation instruments, yet their public documentation does not provide a full dynamic response model for transparent accumulation ranking under changing precipitation. They are therefore listed as weighing references, not ranked transparent accumulation products. For operational totals, they may be useful gauges, yet the public datasheets do not provide enough information to convert static resolution or static weight accuracy into a transparent required-depth ranking for changing rainfall.

Instrument	What is published	Missing transparency item	How it is treated here
MPS / MicroStep-MIS TRwS	0.001 mm resolution and headline intensity / precipitation specifications.	No public time constant, filter kernel, raw/filtered noise, output delay, or residual compensation error.	Static / filtered weighing reference only; not ranked from resolution alone.
Apogee Cloudburst SG-400 series	0.01 mm measurement resolution, cumulative amount accuracy of 0.1 mm below 5 mm and 1% above 5 mm, plus filtering for evaporation, vibration, and temperature.	No public timing model for the filter and compensation algorithm, and no residual dynamic error model for changing rainfall.	Static weighing-total / public-envelope reference; not ranked in the transparent accumulation table.
Geonor T-200B	Vibrating-wire weighing gauge, WMO history, 200 cm² inlet, and sensitivity better than 0.1 mm.	No public dynamic filter/noise/time-response model in the linked manual to convert that sensitivity into an auditable accumulation-floor ranking across changing precipitation.	Historical weighing reference; not ranked in the transparent accumulation table.
FTS/AEM SDI-RAINE-HYDRO	Self-emptying weighing/hybrid product with public amount and intensity envelopes.	No public filter kernel, raw/filtered noise, output-delay model, or step/ramp response sufficient for transparent dynamic ranking.	Weighing/self-emptying precipitation reference; not a stronger dynamic rank.
FTS/AEM AWP all-weather precipitation gauge	All-weather weighing precipitation gauge family with one-minute intensity, total precipitation, rain duration, and filtering/compensation claims.	No full public dynamic model converting static resolution or filtering into a transparent changing-rain measurement floor.	Static/filtered weighing reference only.
Meteoservis MRW500	WMO reference weighing gauge; public materials list 500 cm² collecting area and 0.1 mm pulse simulation.	Exact public time constant/filter/noise model was not extracted from final WMO tables.	Historical WMO reference; not a modern transparent dynamic ranking row.
WMO weighing references: VRG101, older OTT Pluvio / Pluvio 250, PG200, MPA-1M	Historical WMO laboratory/field reference weighing instruments.	Instrument-specific response, filter, and processing details are not represented by a single public row in this article.	Reference-only WMO validation context.

Precipitation is not a static laboratory weight. Rain intensity changes continuously, and water can evaporate, drain, be filtered out as noise, or be corrected by firmware between the beginning and ending states of a measurement window. A weighing gauge that claims evaporation, vibration, or temperature compensation should publish the residual error and the timing model for that compensation before it is assigned a transparent accumulation ranking.

Radar precipitation sensors, smart disdrometers, and other non-catchment rain indicators

Radar precipitation sensors and smart disdrometers are not ranked as catchment rain gauges in this analysis. These sensors do not collect water in a calibrated bucket, funnel, or weighing container. They infer precipitation from radar return strength, Doppler velocity, drop-size classes, and precipitation-type algorithms. This makes them useful for low-maintenance present-weather detection, precipitation-type classification, and dense sensor networks, but it also means their rainfall amount is an algorithmic retrieval rather than a direct catchment measurement.

Laboratory accuracy is not field accuracy. The OTT/Lufft WS100 lists liquid precipitation accuracy under laboratory conditions using a reference-drop simulator with a 2.8 mm drop diameter. The Vaisala PRECICAP RM60 lists 2% precipitation accuracy in laboratory conditions. Natural rain is not a single reference drop; practical drop-count examples for 200 cm², 400 cm², and 533 cm² catchment areas show why real rain must be treated as a changing drop-size distribution. It is a changing mixture of drop sizes, fall speeds, wind effects, turbulence, evaporation below the sensing volume, and sometimes mixed precipitation; drop volume and shape can also be checked with the raindrop shape and size calculator. A radar or disdrometer algorithm must prove its accuracy across those conditions before its laboratory number can be used as a rain-gauge ranking value.

Weather-radar QPE provides the cautionary context. Radar does not directly measure rainfall amount; it measures returned electromagnetic energy and converts it to rain rate through assumptions about drop-size distribution and fall speed. NWS explains that different drop-size distributions can produce the same reflectivity but different rain rates, and that radar rain-rate estimates can vary from true rain rate by a typical factor of two. X-band radar studies similarly show that radar rainfall usually requires gauge adjustment and that short-window, high-resolution radar rainfall uncertainty is often tens of percent or larger.

A radar precipitation sensor is not a rain gauge unless its algorithmic rainfall amount has been field-validated against catchment references over natural drop-size distributions and wind conditions. A laboratory 2% or 10% number should not be used as a field rain-intensity ranking unless the manufacturer publishes the test distribution, wind conditions, retrieval-algorithm limits, measurement volume, and field validation against traceable catchment gauges.

Practical reading: WS100, RM60, WXT-style impact sensors, optical disdrometers, and similar non-catchment precipitation sensors are treated here as reference-only sensors, not ranked rain gauges. They may be valuable for precipitation type, event detection, maintenance-light networks, and radar-network support. They are not assigned a transparent 1-minute, 10-minute, or accumulation accuracy floor unless the manufacturer publishes field-valid dynamic accuracy across natural drop-size distributions, wind speeds, wind directions, mixed precipitation, and changing rain intensity.

Rain sensors / indicators — not ranked as transparent catchment gauges

Caution: the products below can be useful rain indicators, precipitation classifiers, present-weather sensors, radar-network support sensors, or maintenance-light network sensors. From public datasheets alone, they are not reliable transparent determinations of true rain rate or accumulation in the same way as calibrated catchment gauges. Their rainfall amount depends on laboratory algorithms, retrieval assumptions, field conditions, and validation data that are not equivalent to bucket depth, collector area, siphon volume, or a weighed catchment mass.

Sensor class / example	Principle	Public accuracy basis	Main uncertainty issue	Ranking treatment here
OTT / Lufft WS100 radar precipitation sensor / smart disdrometer	24 GHz Doppler radar; reports precipitation type, quantity, intensity, drop-size classes, and particle velocity.	Liquid precipitation accuracy is stated as ±0.16 mm or ±10% of measured value under laboratory conditions using a Lufft reference-drop simulator with 2.8 mm drops and 10–200 mm/h adjustable intensity.	Natural rain is a mixed drop-size distribution, not a single 2.8 mm reference-drop condition. Wind, turbulence, mixed precipitation, and algorithm limits determine field performance.	Reference-only non-catchment sensor. Not ranked against catchment rain gauges from the datasheet alone.
Vaisala PRECICAP® RM60 radar precipitation sensor	61 GHz near-field Doppler radar; reports accumulation, intensity, precipitation type, drop-size distribution, and reflectivity factor.	Datasheet lists 2% precipitation accuracy in laboratory conditions and 22 drop-size classes.	Promising low-maintenance radar sensor, but the public ranking model needs field-valid error across natural DSD, wind, mixed precipitation, retrieval limits, and changing intensity.	Reference-only non-catchment sensor. Not ranked as a transparent rain-gauge accuracy floor without field-validation details.
Vaisala WXT520 / WXT530 / WXT536 class	Non-catchment impact/acoustic precipitation sensing.	Older WXT documentation excludes possible wind-induced error; newer WXT-style specifications describe rainfall accuracy as weather-dependent.	Useful caution example: non-catchment sensors can have large instrument-specific wind and geometry errors that are not captured by a laboratory accuracy line.	Reference-only rain indicator / compact weather-transmitter precipitation channel, not a catchment rain-gauge ranking row.
Optical disdrometers and present-weather sensors	Optical beam interruption, fall-speed classes, hydrometeor classification, and retrieval algorithms.	Manufacturer-specific laboratory or controlled-test statements.	Alignment, splash, wind, DSD, mixed precipitation, classification thresholds, and algorithm assumptions determine field rain-rate accuracy.	Reference-only unless field-corrected and validated against catchment references for the intended site and window length.
Weather radar / X-band radar QPE	Radar reflectivity converted to rain rate over an air volume and then adjusted or merged with gauges.	Operational QPE is generally gauge-adjusted; uncertainty is not a point rain-gauge floor.	Reflectivity-to-rain-rate conversion is not unique because DSD changes; attenuation, beam geometry, vertical profile, and calibration add additional uncertainty.	Valuable spatial rainfall product, not a point catchment-gauge substitute for this ranking table.
Nanoenvi MET radar rain sensor	Radar-based non-catchment precipitation sensing; public materials emphasize radar rain sensing and 0–200 mm/h intensity capability.	Algorithmic radar precipitation indicator, not a calibrated catchment volume.	Use as a compact precipitation indicator/classifier. Validate against catchment references before using as a rain gauge.	Reference-only non-catchment sensor; not ranked.
WeatherFlow Tempest haptic rain sensor	Haptic/impact non-catchment precipitation sensing on a sensor surface.	WeatherFlow support documentation describes limitations and troubleshooting for rain accumulation.	Useful for compact consumer weather stations and event indication. Not a substitute for a traceable catchment rain gauge.	Reference-only impact/haptic indicator; not ranked.
Stratus RG202 / CoCoRaHS-style manual rain gauge	Manual catchment gauge for observer-read totals.	Manual reading is suitable for daily/event accumulation references, not automatic short-window intensity.	Use as a manual accumulation reference and observer-standard context.	Manual reference only; not ranked as automatic intensity product.
WMO historical non-catchment / alternative instruments	Alluvion, Serosi/Nilometre, KNMI electrical rain gauge, PWD22, Parsivel, Thies LPM, WXT510, LCR-PVK ATTEX/DROP.	Laboratory/field intercomparison context; principles include optical, radar, impact, pressure, conductivity, or water-level methods.	Useful for WMO validation history and comparison context.	Reference-only / historical validation context; not ranked as catchment gauges.

Sources: OTT/Lufft WS100 technical data; Vaisala RM60 datasheet; NWS radar-rainfall estimate explanation; X-band radar rainfall adjustment study; Vaisala WXT520 user guide.

Drop-size-distribution background: natural rain is a mixture of drop sizes, not a monodisperse stream. See the practical drop-count references for 200 cm², 400 cm², 533 cm², 8 inch / 325 cm², 10 inch / 500 cm², 800 cm², and 1000 cm² gauge areas.

Siphon TBR storage state is conservatively modelled

Siphon-equipped tipping buckets in the table — KISTERS / HyQuest TB4 in three resolutions, Geolux RG200 and RG400, and the KISTERS / HyQuest TB4 / Campbell CS700 0.01 in row — are ranked using the most conservative siphon-storage assumption: γ_s = 1, the full siphon residual added in quadrature to the bucket residual. A measured siphon-residual fraction would lower these thresholds proportionally.

Sensitivity reference: at γ_s = 0.5, the KISTERS TB4 0.1 mm 1% threshold falls from 17.7 mm to 11.3 mm; at γ_s = 0, it falls to 8.2 mm — still above the 533 cm² class and adjacent to the 400 cm² 0.1 mm class. The qualitative ranking is robust to γ_s; absolute values would shift with vendor-published or independently measured siphon-residual data. See sample calculation 3 in the appendix for the full derivation.

WMO validation layer for historical and exact-model rows

The deterministic analytical floor remains the main ranking metric. WMO 1-minute rainfall-intensity resolution and declared/measured rainfall-intensity range are added as a validation layer so that strong mathematical rows are not over-interpreted outside their tested operating range.

Validation item	How it is used here
WMO 1-minute RI resolution	Flags whether a gauge can report rainfall intensity with enough resolution for 1-minute products.
Declared or WMO-tested RI range	Flags rows where the 1-minute equivalent of a 1% target would be outside the tested or declared intensity range.
Correction class	Labels no correction, pulse correction, software correction, mechanical correction, siphon flow control, or weighing/filtering.
Ranking treatment	Separates main-ranked rows from alias-only rows, reference-only non-catchment rows, and unranked weighing references.

Manufacturer envelope validity bands

The analytical-floor ranking in the main tables above assumes each gauge is operating within its published manufacturer envelope. For accumulation totals, the relevant question is whether the tipping mechanism, siphon, or weighing element behaves correctly at the highest instantaneous rates that the daily or event total contains. The matrix below summarizes typical envelope behavior by row category. For a specific application, always check the candidate gauge's published datasheet.

Row category	Amount accuracy floor (low and moderate rate)	Above ~250 mm/h instantaneous rate	Above ~500 mm/h or near load-cell saturation	Notes for accumulation totals
TBR Raw-pulse tipping bucket (0.1, 0.2, 0.254, 0.5 mm)	±1–3% per datasheet (vendor-specific)	Dynamic tip-rate loss reduces accumulated total; uncorrected output may underestimate by 5–15%+ during high-intensity bursts	Significant undercounting unless dynamic correction is applied (Calder & Kidd 1978; Niemczynowicz 1986; Marsalek 1981)	Daily totals containing high-intensity bursts inherit the dynamic-loss bias of those bursts
IoT³ Phase-aware tipping bucket	±1% Barani field-performance statement	Same dynamic loss as raw-pulse equivalent of same hardware (phase code does not mitigate mechanical tip rate)	Same as raw-pulse	For accumulation totals, IoT³ ties wired (B=3 does not anchor unbracketed event boundaries); dynamic loss applies equally
Siphon Siphon-equipped tipping bucket	±2% (e.g. KISTERS TB4 to 250 mm/h)	Spec'd ±3% (KISTERS TB4 to 500 mm/h); siphon buffer extends valid band substantially beyond raw-pulse TBRs	Above published envelope; siphon overflow possible	Siphon TBRs are designed for hydrologic accumulation in storm-prone climates; the siphon-storage residual γ_s discussed in the main ranking is the trade-off
Weighing Public envelope, amount-derived (Pluvio² Accu NRT, rain[e] amount)	±0.1 mm or ±1%, rate-independent	Same; weighing measures mass, not tip count, so dynamic tip loss does not apply	Bounded by load-cell capacity (typical 1500–3000 mm cumulative depth before vessel must be emptied)	For accumulation totals, weighing is fundamentally rate-resilient up to load-cell saturation; this is the main weighing advantage at this horizon

Reference: Lambrecht rain[e] hi-resolution state-model layers

These rows are not in the main accumulation ranking. They are mathematical state-resolution model potential layers — what the analytical floor would predict if a 0.001 mm scale-state or 0.01 mm pulse-state could be lifted to a real-time amount product without measured weighing response, filtering, and self-emptying-correction validation. The defensible Lambrecht row at this horizon is the public envelope (10 mm at 1%, included in the main ranking above). The model rows below are useful for understanding the technology potential, not for product selection.

Table navigation: scroll left and right inside the table box to see all columns. The rank and gauge columns remain pinned; notes and technical evidence columns sit farther to the right.

M-rank	Lambrecht model layer	P_min at 1% (mm)	P_min at 2% (mm)	1% @30 min (mm/h)	1% @1 h (mm/h)	1% @3 h (mm/h)	1% @6 h (mm/h)	1% @24 h (mm/h)	Δ_res (mm)	Evidence layer	State detail	A (cm²)	d / d_eq (mm)	V_s (mL)	Why it ranks here
M1	Model only Lambrecht rain[e]400 — 0.001 mm hi-res scale-state model	0.635	0.166	1.27	0.635	0.212	0.106	0.0265	0.001	rain[e] hi-res state model	scale state: ≈6.64 bits	400	0.1	—	Model-potential layer; requires measured weighing response, filtering, and delay before being treated as a real-time claim.
M2	Model only Lambrecht rain[e]314 — 0.001 mm hi-res scale-state model	0.804	0.207	1.61	0.804	0.268	0.134	0.0335	0.001	rain[e] hi-res state model	scale state: ≈6.99 bits	314	0.1274	—	Model-potential layer; requires measured weighing response, filtering, and delay before being treated as a real-time claim.
M3	Model only Lambrecht rain[e]400 — 0.01 mm hi-res pulse-state model	1.19	0.494	2.37	1.19	0.396	0.198	0.0495	0.01	rain[e] hi-res state model	pulse state: ≈3.32 bits	400	0.1	—	Model-potential layer; requires measured weighing response, filtering, and delay before being treated as a real-time claim.
M4	Model only Lambrecht rain[e] / rain[e]LP / rain[e]H3 — 0.001 mm hi-res scale-state model	1.25	0.318	2.51	1.25	0.418	0.209	0.0523	0.001	rain[e] hi-res state model	scale state: ≈7.64 bits	200	0.2	—	Model-potential layer; requires measured weighing response, filtering, and delay before being treated as a real-time claim.
M5	Model only Lambrecht rain[e]314 — 0.01 mm hi-res pulse-state model	1.31	0.52	2.61	1.31	0.435	0.218	0.0544	0.01	rain[e] hi-res state model	pulse state: ≈3.67 bits	314	0.1274	—	Model-potential layer; requires measured weighing response, filtering, and delay before being treated as a real-time claim.
M6	Model only Lambrecht rain[e] / rain[e]LP / rain[e]H3 — 0.01 mm hi-res pulse-state model	1.65	0.593	3.31	1.65	0.551	0.276	0.0689	0.01	rain[e] hi-res state model	pulse state: ≈4.32 bits	200	0.2	—	Model-potential layer; requires measured weighing response, filtering, and delay before being treated as a real-time claim.

Reference: Lambrecht 1-minute intensity timing in plain language

For readers who want to understand why the public Lambrecht envelope rather than the hi-resolution state model is used in the main ranking:

Publicly defined item	Plain-language meaning	Why it matters here
6 measurements per minute	The 1-minute intensity is built from six 10-second measurement steps.	The native 1-minute intensity product behaves like a 60-second trailing moving sum, not like an instantaneous inter-tip measurement.
Moving sum of the last 6 values	Each new value is combined with the previous five values to form "intensity within the last minute."	A new rainfall step appears gradually during the first minute and then exits the product after it is older than 60 seconds.
Self-emptying by tipping	When one chamber is full, the vessel tips and weighing continues in the other chamber.	The tip should not erase rainfall from the total amount. It creates a correction event that must be timed and filtered correctly.
Multi-stage filtering	Wind, shock, and vibration are filtered before the weight increase is evaluated.	Filtering reduces noise and can also delay or smear short-window intensity changes.
Variance over 4 s	The instrument can output a short-term variance/quality value.	This acknowledges noise. It is not the same as a published numerical load-cell noise specification.

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Appendix — methodology, sample calculations, and source data

This appendix gives the full mathematical model, a worked sample calculation for each product category in the comparison set, two visualizations of the full ranking, and a list of source documents. Any reader can reproduce every number in the article above using the formulas and inputs below.

A1. Methodology in plain language

The equations below generalize the same resolution-and-depth logic shown in the simpler Rain Gauge Accuracy Tables and the rain-intensity error guide.

The model decomposes the total uncertainty at a reporting interval into two independent parts: a per-tip stochastic floor (random variation in the volume of water needed to tip the bucket, or the equivalent state-resolution variation for a weighing product) and a boundary-state residual (unresolved water at the start and end of the reporting interval). The two parts add as variances. The expanded uncertainty uses the GUM convention U95 = 2σ_total. The minimum rainfall depth needed to reach a target relative uncertainty q is the positive root of a quadratic equation derived from U95(P)/P = q.

σ_tip = 0.05 / (0.1 · A) (per-tip stochastic floor; A = collector area in cm²)

σ_B² = (Δ_start² + Δ_end²) / 12 (boundary residual variance, uniform-distribution assumption)

σ_total²(P) = σ_B² + (P/d) · σ_tip² (total variance at reporting interval depth P)

U95(P) = 2 · σ_total(P) (expanded uncertainty, GUM coverage factor k = 2)

P_min = [4σ_tip²/d + √( (4σ_tip²/d)² + 16 q² σ_B² )] / (2 q²) (solve U95(P_min)/P_min = q)

For ordinary tipping buckets transmitting only pulses (B = 0), Δ_start = Δ_end = d (the tip depth). For a phase-aware tipping bucket transmitting a B-bit phase code with both window boundaries inside an active rain event (the "B3/B3 interior" case), Δ = d / 2^B. For a daily or event total where the start and end occur in dry conditions, Δ = d (the phase code does not anchor unbracketed event boundaries — this is why the IoT³ family ties the wired version in this ranking). For siphon-equipped TBRs, the effective Δ is increased by the siphon-storage residual: σ_B² = (d² + γ_s² · s²) / 6 where s = 10 · V_s / A is the depth-equivalent siphon storage (V_s in mL, A in cm²) and γ_s ∈ [0, 1] is the unresolved-residual fraction (γ_s = 1 in this table; conservative). For weighing products without a published per-tip stochastic floor, the public manufacturer envelope is used directly: U_amount = max(0.1 mm, 0.01 · P), giving P_min = 10 mm at the 1% target.

A2. Worked sample calculations — one per product category

Calculation 1 — Raw-pulse tipping bucket (Lambrecht 15189 0.2 mm, 200 cm²)

Inputs: A = 200 cm², d = 0.2 mm, B = 0 (no phase code transmitted)

σ_tip: 0.05 / (0.1 · 200) = 0.05 / 20 = 0.0025 mm

σ_B²: Δ_start = Δ_end = d = 0.2 mm → σ_B² = 2(0.2²)/12 = 0.08/12 = 0.006667 mm²

Quadratic at q = 0.01: q² = 1×10⁻⁴; 4σ_tip²/d = 4(0.0025²)/0.2 = 1.25×10⁻⁴; 4σ_B² = 0.02667

Discriminant: (1.25×10⁻⁴)² + 4(1×10⁻⁴)(0.02667) = 1.56×10⁻⁸ + 1.067×10⁻⁵ = 1.069×10⁻⁵; √ = 3.270×10⁻³

P_min: (1.25×10⁻⁴ + 3.270×10⁻³) / (2 × 1×10⁻⁴) = 3.395×10⁻³ / 2×10⁻⁴

P_min(1%) = 16.97 mm — matches the table value for any 200 cm² 0.2 mm raw-pulse TBR (Lambrecht 15189, MicroStep MR2, MeteoRain 200 Pro 0.2 mm, Seven Sensor Solutions 3S-RG, Vaisala QMR101, Pronamic Professional)

Calculation 2 — IoT³ phase-aware TBR (MeteoRain IoT³ 400 Aero, B3/B3 short-window only)

Inputs: A = 400 cm², d = 0.1 mm, B = 3 (3-bit phase code), both boundaries bracketed by tips (interior of active rain event)

σ_tip: 0.05 / (0.1 · 400) = 0.05 / 40 = 0.00125 mm

σ_B² (B3/B3): Δ = d / 2³ = 0.1/8 = 0.0125 mm; σ_B² = 2(0.0125²)/12 = d²/384 = 0.01/384 = 2.604×10⁻⁵ mm²

Quadratic at q = 0.01: 4σ_tip²/d = 4(0.00125²)/0.1 = 6.25×10⁻⁵; 4σ_B² = 1.042×10⁻⁴

Discriminant: (6.25×10⁻⁵)² + 4(1×10⁻⁴)(1.042×10⁻⁴) = 3.91×10⁻⁹ + 4.168×10⁻⁸ = 4.56×10⁻⁸; √ = 2.135×10⁻⁴

P_min: (6.25×10⁻⁵ + 2.135×10⁻⁴) / 2×10⁻⁴ = 2.760×10⁻⁴ / 2×10⁻⁴

P_min(1%, B3/B3 short-window) = 1.380 mm — applies only to ongoing intensity windows interior to active rain. For daily/event totals (B0/B0), repeat the calculation with σ_B² = d²/6 = 1.667×10⁻³ mm² → P_min(1%, B0/B0 daily) = 8.483 mm, identical to the wired MeteoRain 400 Aero and to every other 400 cm² 0.1 mm raw-pulse TBR.

Calculation 3 — Siphon TBR (KISTERS / HyQuest TB4 0.1 mm, V_s = 12 mL)

Inputs: A = 628.3 cm², d = 0.1 mm, V_s = 12 mL, γ_s = 1 (conservative, full siphon residual unresolved)

σ_tip: 0.05 / (0.1 · 628.3) = 0.05 / 62.83 = 7.957×10⁻⁴ mm

Depth-equivalent siphon storage: s = 10 · V_s / A = 10 · 12 / 628.3 = 0.191 mm

σ_B² (bucket + siphon): (d² + γ_s² · s²) / 6 = (0.01 + 1·0.0365) / 6 = 0.0465/6 = 0.007746 mm²

Quadratic at q = 0.01: 4σ_tip²/d = 4(7.957×10⁻⁴)²/0.1 = 2.532×10⁻⁵; 4σ_B² = 0.03098

Discriminant: (2.532×10⁻⁵)² + 4(1×10⁻⁴)(0.03098) = 6.41×10⁻¹⁰ + 1.239×10⁻⁵ ≈ 1.239×10⁻⁵; √ = 3.521×10⁻³

P_min: (2.532×10⁻⁵ + 3.521×10⁻³) / 2×10⁻⁴

P_min(1%, γ_s = 1) = 17.73 mm. At γ_s = 0.5: P_min = 11.3 mm. At γ_s = 0 (siphon residual fully resolved): P_min = 8.16 mm.

Calculation 4 — Weighing public envelope (OTT Pluvio² S Accu NRT)

Inputs: Public manufacturer envelope U_amount = max(0.1 mm, 0.01 · P)

Solve U_amount / P ≤ q at q = 0.01: max(0.1/P, 0.01) ≤ 0.01 → 0.1/P ≤ 0.01 → P ≥ 10 mm

P_min(1%) = 10 mm. At q = 0.02: P ≥ 5 mm. At q = 0.03: P ≥ 3.333 mm. The public-envelope row uses the manufacturer specification directly without a stochastic-floor model. Same result for OTT Pluvio² L Accu NRT, Lambrecht rain[e] amount-total, and rain[e]one Modbus amount-total.

Calculation 5 — Lambrecht hi-resolution scale-state model layer (rain[e]400, Δ_res = 0.001 mm, model only)

Inputs: A = 400 cm², d_eq = 0.1 mm, Δ_res = 0.001 mm (advertised scale resolution treated as effective state resolution in the model)

σ_tip: 0.05 / (0.1 · 400) = 0.00125 mm (same as MeteoRain IoT³ 400 Aero)

σ_B²: 2(Δ_res)²/12 = (0.001)²/6 = 1.667×10⁻⁷ mm²

Quadratic at q = 0.01: 4σ_tip²/d = 6.25×10⁻⁵; 4σ_B² = 6.667×10⁻⁷

Discriminant: (6.25×10⁻⁵)² + 4(1×10⁻⁴)(6.667×10⁻⁷) = 3.91×10⁻⁹ + 2.667×10⁻¹⁰ = 4.173×10⁻⁹; √ = 6.460×10⁻⁵

P_min: (6.25×10⁻⁵ + 6.460×10⁻⁵) / 2×10⁻⁴

P_min(1%, model layer) = 0.6355 mm. Caveat: this assumes the advertised scale resolution can be lifted to a defensible real-time amount product. In practice this requires a measured weighing time constant, filter bandwidth, dead-time, and self-emptying-correction interval. Without that validation, the row sits in the reference sub-table above as model potential, not in the operative ranking.

A3. Additional visualization

Figure A2. Required rainfall depth as a function of the relative uncertainty target q for one representative product from each category. The weighing public envelope (red curve) is fundamentally different from the tipping-bucket curves: it follows P_min = 0.1/q (a hyperbola) because the floor is a fixed amount-resolution rather than a stochastic per-tip floor. The phase-aware short-window curve sits an order of magnitude below the same hardware in B0/B0 daily mode.

A4. Conflict-of-interest and funding statement (full)

The author is the chief executive officer and a founder of Barani Design Technologies, the manufacturer of the MeteoRain product family included in the comparison. The MeteoRain wired and IoT³ rows occupy several positions throughout the ranking, including ties at the top of the tipping-bucket category (because the 0.075 mm tip depth of the 533 Classic is currently the smallest in the comparison set). The author has no financial relationship with the other manufacturers (KISTERS / HyQuest, OTT HydroMet, Lambrecht, Geolux, Vaisala, Texas/Campbell, Casella, Davis, Onset HOBO, Met One, RainWise, MicroStep / Meteoservis, AEM/FTS, CAE, Pronamic, Seven Sensor Solutions, EML).

The work was not funded by any vendor of any compared product. No external party reviewed, edited, or approved this article prior to publication. All inputs are publicly available datasheets and operating manuals; no proprietary, internal, or vendor-supplied data was used for any product, including the author's own products. Conservative modelling parameters are applied uniformly: U95 = 2σ_total (GUM coverage factor k = 2, more conservative than the previously used triangular-distribution k = 1.90); γ_s = 1 for siphon TBRs (the most conservative defensible value, applied to competitor siphon products that the author does not manufacture); B0/B0 boundary regime for accumulation totals (which means the IoT³ family ties the wired version at this horizon, a conservative choice that disadvantages the author's own product compared to the favourable B3/B3 interior bound).

Designing a measurement instrument requires a working uncertainty model of the same instrument; the author's role as instrument designer is therefore not separable from the author's role as analyst. The appropriate response to this dual role is transparency rather than recusal. Readers who suspect bias are encouraged to substitute alternative parameter values into the formulas in section A1, re-run any sample calculation in section A2, and verify whether the conclusions change. The full peer-reviewed manuscript with detailed derivations is available on request.

A5. Source notes and verification

WMO dynamic-response support: the WMO Past CIMO Intercomparisons summary states that weighing gauges can show lower uncertainty than tipping-bucket gauges under constant flow after stabilization, and also states that rainfall-intensity measurement is affected by acquisition-system response time, internal software filtering caused significant delays, and only one weighing instrument met the WMO 1-minute rainfall-intensity requirement. The WMO/JMA laboratory-intercomparison summary describes the weighing-gauge step-response test by switching flow from 0 to 200 mm/h and back to 0 and observing stabilization with delay resolution finer than 1 minute.

Apogee Cloudburst and Geonor T-200B are listed as unranked weighing references in this revision. Apogee publishes cumulative amount and rate/intensity accuracy together with filtering for evaporation, vibration, and temperature, while Geonor publishes a vibrating-wire weighing architecture and sensitivity better than 0.1 mm. Neither linked public document provides the dynamic filter/noise/time-response model needed for the transparent short-window or event-total ranking used in the main tables.

BARANI MeteoRain product sizes and IoT³ descriptions: MeteoRain product overview and MeteoRain IoT.

KISTERS / HyQuest TB4 Series II rows: documented siphon storage volume V_s = 12 mL applied with γ_s = 1 conservative residual fraction. Reference: KISTERS TB4 Series II user manual (publicly available).

Geolux RG200/RG400 siphon rows: working values RG200 ≈ 8 mL and RG400 ≈ 16 mL, both at approximately 4 mL/tip. Seven Sensor Solutions 3S-RG is treated as a non-siphon 200 cm² 0.2 mm tipping bucket.

OTT Pluvio² S/L treatment: Accu NRT / Accu total NRT accumulation products are separated from Intensity RT (which appears in the companion intensity ranking, not here) because the two outputs have different purpose, delay, and product validity definitions. Reference: OTT Pluvio² S/L datasheet and operating instructions (publicly available).

Lambrecht rain[e] family: public envelope (0.1 mm or 1% amount accuracy floor) and operating manual (6 measurements per minute, 60-second moving sum, self-emptying compensation, multi-stage filtering, 4-second variance output). The hi-resolution 0.001 mm scale-state and 0.01 mm pulse-state model layers are presented as reference rows only (see "Reference: Lambrecht rain[e] hi-resolution state-model layers" sub-table above).

MPS / MicroStep-MIS TRwS weighing gauges are listed as unranked weighing references. The checked public documents publish resolution and headline intensity specifications, but they do not publish the response-time, filter-kernel, raw/filtered noise, output-delay, or residual compensation-error data required for a transparent short-window dynamic ranking. References: MPS TRwS_E and MicroStep-MIS TRWS_E.

Additional gauges added in this revision: Précis Mécanique 3039/1 dynamic bucket (1000 cm², 0.1 mm), EML / In-Situ / Campbell ARG314 (314 cm², 0.1/0.2 mm public Campbell configurations, with optional 0.5 mm treated as a technical row), METER ECRN-100 (16.0 cm collector, 0.2 mm), Observator/RIMCO RIM-7499 siphon gauge (203 mm, 0.2/0.25/0.5 mm), Rika/Honde/Renke 200 mm OEM tipping-bucket classes, and Tamaya/Ikeda KDC-S13-RT-5E 200 mm / 0.5 mm. Campbell ARG100 remains represented by the existing Vaisala QMR102 / EML ARG100 / Campbell ARG100 row. SPIEA is listed as a manual accumulation reference only and is not ranked as an automatic short-window intensity product.

All other listed competitors (Vaisala, Texas/Campbell, Casella, Davis, Onset HOBO, Met One, RainWise, MicroStep / Meteoservis, AEM/FTS, CAE, Pronamic, EML) are modelled from publicly available datasheets and product manuals using the formulas in section A1 above. No proprietary data is used.

The full mathematical model, derivation, and sensitivity analyses are documented in the v23 manuscript "Low-Power Rain-Gauge Uncertainty Models" (Barani, 2026), available on request. The companion intensity ranking article uses the same model with the boundary regime swapped to B3/B3 (interior to active rain).

Additional v25 ranked rows: Précis Mécanique 3039/1 is entered as a 1000 cm² / 0.1 mm pulse-output dynamic-bucket gauge; EML / In-Situ / Campbell ARG314 is entered as 314 cm² with 0.1, 0.2, and optional 0.5 mm configurations; METER ECRN-100 is entered as a 16.0 cm collector / 0.2 mm double-spoon pulse gauge; Rika, Honde, and Renke products are grouped into 200 mm diameter / 0.1, 0.2, and 0.5 mm pulse-output classes where those configurations are listed; Tamaya / Ikeda KDC-S13-RT-5E is included in the 200 mm diameter / 0.5 mm class; Observator / RIMCO RIM-7499 is entered as a 203 mm siphon-controlled TBR at 0.2, 0.25, and 0.5 mm. SPIEA is retained as a manual reference gauge only and is not ranked in automatic intensity tables.

v40 additions: CAE PMB2 / PMB2/R and ETG R102 are added as 1000 cm² / 0.2 mm pulse-output tipping-bucket rows. Their published correction algorithms are noted but not applied in the transparent required-depth model because the ranking uses the public collector area, tip depth, and state model rather than unpublished or product-specific correction code.

V42 WMO/historical additions. Added ranked rows include FTS/AEM RG-T options, KISTERS/HyQuest TB6/TB3 variants, AP23/PAAR, Meteoservis MR3H, Thies PT, R01 3070 / Précis-Mécanique, SIAP UM7525, MTX PP040, LSI Lastem DQA031, WaterLOG H-340SDI, India Met Dept. TBRG Mk2, Yokogawa WMB01, and Hydrological Services TB-3 exact siphon row. Alias-only labels and reference-only non-catchment/weighing rows are separated so duplicate names do not distort the ranked catchment-gauge tables.