El Nino Watch
A global reconstruction of past weather by the European centre (ECMWF), about 25 km resolution, available with about 5 days delay. Used for Samui's observed rain and its 1991-2020 normals.
Data and trust
ERA5 combines weather stations, aircraft, buoys, radar and satellite observations with a weather model to estimate the weather everywhere, every hour, from 1940 to about 5 days ago (served here through Open-Meteo).
The app uses it for the Samui rain totals (30/60/90/180 days) and for the 1991-2020 normals they are compared with. Comparing ERA5 with ERA5 keeps the comparison fair, even if ERA5 misses some local extremes.