Unless you don't mind the almost daily torrential rain of the monsoon, the best time to visit Chiang Mai is between October and April; the other months are a virtual washout. The mildest temperatures are in December and January. Nights in Chiang Mai are regularly cooler than in southern Thailand.
It can be quite hot in Chiang Mai, with the April average temperature 36°C (95°F). Nights are regularly cooler than in southern Thailand.
| Month | Temp (°C) | Rainfall (mm) | Humidity (%) | Sunshine (hours) |
| Jan | 13 - 29 | 0 | 9 | |
| Feb | 14 - 32 | 10 | 9 | |
| Mar | 17 - 34 | 8 | 9 | |
| Apr | 22 - 36 | 36 | 9 | |
| May | 23 - 34 | 122 | 8 | |
| Jun | 23 - 32 | 112 | 6 | |
| Jul | 23 - 31 | 213 | 5 | |
| Aug | 23 - 31 | 193 | 4 | |
| Sep | 23 - 31 | 249 | 6 | |
| Oct | 21 - 31 | 94 | 7 | |
| Nov | 19 - 30 | 31 | 8 | |
| Dec | 15 - 28 | 13 | 9 |