El Nino Watch

RainViewer (rain radar mosaic)

A worldwide mosaic of national weather radars, updated every 10 minutes. The map shows the newest frame and its time.

Map layers

RainViewer collects the images of public weather radars (the Thai Meteorological Department's among them) and joins them into one map. The app asks RainViewer which frames exist and shows the newest past frame; its time is printed with the layer.

How to read it

  • Colours = rain intensity (light blue light rain, yellow/red heavy rain, purple very heavy or hail).
  • Only where a radar reaches (about 200-250 km from each radar). Outside, the map is empty, which does not mean dry.
  • Frames are past radar images, not a forecast.

Why it matters for Koh Samui

Radar shows a rain band approaching the Gulf of Thailand in the next hour or two, useful before a ferry crossing or a drive in a monsoon surge.

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)