El Nino Watch

Cold / winter severity

Scored from the mean temperature of the coldest month (ERA5 1991-2020), with frost days and yearly snowfall in the note.

Hazards

The coldest month mean summarises how hard winter is: heating needs, frozen roads, snow clearing. Frost days = days with a minimum below 0 °C. Snowfall is in cm of fresh snow per year.

Why it matters for Koh Samui

Cold is a real hazard for health, housing (insulation, heating fuel) and daily life, and a big change for anyone used to the tropics.

Thresholds

Coldest month meanExposure
>= 10 °C0 very low
3 to 10 °C1 low
-3 to 3 °C2 moderate
-10 to -3 °C3 high
< -10 °C4 very high

Exposure scale: 0 very low, 1 low, 2 moderate, 3 high, 4 very high. Higher = more exposed. The colour of the matrix cell follows the same scale.

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)