Chiang Mai weather in September
Temperature, sea and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Fair
Best time to visit: November – January
What is the weather like in Chiang Mai in September?
In September, Chiang Mai is hot: daytime highs average 29 °C, and even at night it stays warm at around 23 °C. Expect around 5 hours of sunshine a day. It is the rainy season: rain falls on about 24 days, totalling 230 mm. On about 12 days the thermometer climbs to 30 °C or more. The air is often humid and muggy. All in all, September is a so-so month for a holiday in Chiang Mai.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 38 | 41 | 52 |
| Day | 29° | 29° | 29° |
| Night | 24° | 23° | 22° |
| Sun | 4 h | 5 h | 6 h |
| Rain days | 25 | 24 | 16 |
More details for September
- Daylight
- 12 h 16 min06:11 – 18:27
- UV index
- 12 · extremeclear sky, noon (estimate)All months
- Muggy days
- 30 daysdew point 18 °C or more
- Wind
- 7 km/haverage daily peak
- Cloud cover
- 85 %on average
- Hot days
- 12 days30 °C or more
- Time zone
- UTC+7Asia/Bangkok
How the score comes together
- Temperatureweight 50 %70 %
- Sunshineweight 20 %32 %
- Few rainy daysweight 30 %0 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in September
- Sunscreen
- Sunglasses & sun hat
- Light, breathable clothes
- Water bottle – drink plenty
- Insect repellent
- Rain jacket or umbrella
Chiang Mai in September: quick answers
Is Chiang Mai hot in September?
Yes. In September, Chiang Mai is hot: daytime highs average 29 °C and nights stay around 23 °C. On about 12 days the thermometer climbs to 30 °C or more.
Does it rain much in Chiang Mai in September?
It rains often – on about 24 days, adding up to 230 mm.
Chiang Mai month by month
The whole year in Chiang MaiAll destinations: ThailandWhere to go in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, GeoNames (CC BY 4.0)