Data and trust
NASA SMAP radiometer, JPL CAP algorithm, 8-day running mean.
Limits. Less reliable within ~40 km of coasts (so around Samui itself).
How to read it
PSU, scale 30-40; open ocean ~34-35. Fresher = heavy rain or river water.
Why it matters for Koh Samui
During El Nino the fresh water under the Pacific rain band moves east; in the Gulf of Thailand fresher water follows big rain and river floods.
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)