Chiang Mai weather by month
Chiang Mai runs from about 22°C in January to 32°C in April, with July the wettest month at 504 mm.
warmest month
April
32°C
coolest month
January
22°C
wettest month
July
504 mm
worst air month
April
54 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 22°C | 22 mm | 331 h | 28 |
| February | 24°C | 4 mm | 318 h | 30 |
| March | 28°C | 9 mm | 334 h | 39 |
| April | 32°C | 10 mm | 341 h | 54 |
| May | 29°C | 396 mm | 323 h | 16 |
| June | 27°C | 302 mm | 305 h | 10 |
| July | 26°C | 504 mm | 283 h | 13 |
| August | 26°C | 455 mm | 243 h | 14 |
| September | 26°C | 380 mm | 257 h | 15 |
| October | 26°C | 284 mm | 320 h | 19 |
| November | 24°C | 41 mm | 300 h | 20 |
| December | 23°C | 20 mm | 328 h | 27 |
About 3,683 hours of sun a year. Roughly 188 rainy days a year.
These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.
where these numbers come from
- · Temperature, rainfall and sunshine: ECMWF ERA5 reanalysis climate normals via Open-Meteo (CC BY 4.0), fetched once and stored.
- · PM2.5: Copernicus CAMS reanalysis, monthly means. Modelled, not station readings; near coasts CAMS counts sea salt as PM2.5 and reads high.
Last reviewed 2026-05-22. Full method, licences and the list of sources we rejected are on the methodology page.