Hate The Rain checks the sky over Chiang Mai, Chiang Mai every few minutes and tells you when rain starts, how long it lasts and when it stops. Turn on alerts and we ping you before you get soaked.
Tropical monsoon. The southwest monsoon brings heavy rain to most of the country, while the Gulf coast around Koh Samui gets its wettest months later in the year.
Rainiest period around Chiang Mai: May to October (October to December on the Gulf coast). That is when alerts save the most shoes.
For Thailand, the reference agency is Thai Meteorological Department. Forecasts use the best local weather model available, live radar comes from RainViewer, and nearby rain gauges confirm when rain has really stopped wherever they exist.