El Nino Watch

Heavy-rain stations (ThaiWater gauges)

Rain gauges of the national ThaiWater network that measured heavy (35.1-90 mm) or very heavy (more than 90 mm) rain in the last 24 hours, using the TMD rain classes.

Hazards

ThaiWater, run by the Hydro-Informatics Institute (HII), publishes the 24-hour rain of about 4,400 telemetered gauges across Thailand (read in one request every run). The map shows only the stations at 35.1 mm or more, graded with the TMD daily classes (see TMD rain amount classes). Smaller amounts still count in the per-province summary (maximum, number of stations, top station).

How to read it

Round icons with a cloud and rain drops. Click one for the station name, province, the 24-hour total and the time of the reading. Many red icons close together = a flooding risk for the rivers downstream in the next 1-3 days.

Why it matters for Koh Samui

Rain measured today becomes river floods tomorrow, especially in the Chao Phraya basin that drains to Bangkok. Very heavy rain on the Gulf coast can also close piers and roads to the ferries.

Thresholds

Class (TMD)Rain in 24 hColour on the map
Heavy rain35.1 to 90.0 mmOrange
Very heavy rain90.1 mm or moreRed

1 mm = 1 litre per square metre. Stations below 35.1 mm are not drawn.

Sources

Related

ENSO status now

ONI (NOAA CPC)
+1.80 °C, JJA 2026 (previous +1.39 °C)
RONI (NOAA CPC)
+1.36 °C, JJA 2026
Nino 3.4 weekly (NOAA CPC / OISST)
+3.0 °C anomaly, week of 16 Sep 2026 (SST 29.6 °C)