Samui last 30 days vs normal (NASA POWER)

Forecasts and bulletins

Built from NASA POWER: 30-day rain total, the normal total for the same days, the percentage of normal, and the mean temperature with its normal and anomaly.

Limits. Grid-cell values; the normals are 2001-2020, not 1991-2020.

How to read it

precip_pct_of_normal below ~60 % for several weeks in October-December would be an El Nino-type dry monsoon. At 2026-09-21: 186 mm (111 % of normal), 28.7 degC (+0.7).

Why it matters for Koh Samui

The island's water supply depends on the October-December rains.

Sources

• power.larc.nasa.gov

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)