El Nino Watch

Factor: marine heat / coral bleaching

NOAA Coral Reef Watch Degree Heating Weeks for the Gulf of Thailand stations. Context only: it can raise the overall level to Watch at most.

Koh Samui watch

Uses the latest DHW of the Coral Reef Watch stations, preferring those around Samui and the Gulf of Thailand. Stale if the newest value is more than 10 days old.

Thresholds

DHWNOAA meaningFactor level
below 4 °C-weeksbelow Alert Level 10 Normal
4 to 8Alert Level 1 (reef-wide bleaching risk)1 Watch
8 or moreAlert Level 2 or higher (mortality likely)2 (counts as 1 in the overall level)

Cap: 1. Not a critical factor.

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)