Chiang Mai weather in September
September is one of the least pleasant months in Chiang Mai: highs of 27°C (81°F) and about 222 mm (8.7 in) of rain on average. Nights average 20°C (68°F) and cloud cover 89% (NASA POWER, 2001–2025 averages). It is the 2nd wettest month of the year and the 5th coolest. Compared with August, it is about as warm and about as wet; October brings highs of 26°C (80°F) and 123 mm (4.8 in) of rain.
Is September a good time to visit Chiang Mai?
least pleasant month Weather score 45/100.
September is one of the least pleasant months for weather in Chiang Mai. For better conditions, consider Nov–Mar.
Does it rain a lot in Chiang Mai in September?
Yes, it is one of the rainy months: about 222 mm (8.7 in) falls in an average September. It is the 2nd wettest month of the year.
How warm is Chiang Mai in September?
Days average 27°C (81°F) and nights 20°C (68°F).
Chiang Mai weather by month
| Month | High | Low | Rain | Cloud | Weather |
|---|---|---|---|---|---|
| January | 26°C (78°F) | 13°C (56°F) | 15 mm | 28% | best |
| February | 29°C (85°F) | 14°C (58°F) | 5 mm | 21% | best |
| March | 32°C (90°F) | 17°C (62°F) | 23 mm | 32% | best |
| April | 34°C (93°F) | 20°C (69°F) | 63 mm | 47% | fair |
| May | 31°C (88°F) | 21°C (69°F) | 189 mm | 80% | least pleasant |
| June | 29°C (85°F) | 21°C (69°F) | 141 mm | 94% | fair |
| July | 28°C (83°F) | 20°C (69°F) | 178 mm | 95% | least pleasant |
| August | 27°C (81°F) | 20°C (69°F) | 237 mm | 95% | least pleasant |
| September | 27°C (81°F) | 20°C (68°F) | 222 mm | 89% | least pleasant |
| October | 26°C (80°F) | 19°C (66°F) | 123 mm | 69% | fair |
| November | 25°C (78°F) | 16°C (61°F) | 37 mm | 41% | best |
| December | 24°C (76°F) | 14°C (56°F) | 13 mm | 34% | best |
Sources: 2001–2025 monthly averages from NASA POWER (MERRA-2 reanalysis). Page updated . How we rate months