Weather in Chiang Mai in September 2025
- September is usually the wettest month of the year in Chiang Mai;
Average weather
Average temperature in Chiang Mai in September
Going from a maximum of +95°F during the day to a minimum of +75°F during the night, the temperature in September averages around +90°F.
The average maximum temperature goes down 55% by the end of the month, compared with the beginning of the month, from +93°F to +82°F.
Is Chiang Mai warm or cold in September?
Chiang Mai is typically hot in September.
Maximum temperatures go up compared to the previous month from +90°F to +90°F. The minimum temperature also goes down from +77°F to +75°F.
Make sure that you pack your summer linen and swimming costumes; it’s probably going to be hot.
Take a look at how September is compared to other months in Chiang Mai:
Climate in Chiang Mai in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +90°F | +90°F | +88°F | ||||
| Min. temperature | ||||||
| +72°F | +68°F | +59°F | ||||
| Max. temperature | ||||||
| +100°F | +97°F | +99°F | ||||
| Rainfall | ||||||
| 219 mm | 190 mm | 114 mm | ||||
| Wind | ||||||
| 1 m/s | 0 m/s | 0 m/s | ||||
| Humidity | ||||||
| 78% | 79% | 77% | ||||
| Air pressure | ||||||
| 1005 HPa | 1008 HPa | 1011 HPa | ||||
| Sunny days | ||||||
| 0 | 0 | 4 | ||||
| Cloudy days | ||||||
| 1 | 1 | 4 | ||||
| Rainy days | ||||||
| 22 | 16 | 15 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
September weather is still as ok as in August. The temperature levels stay the same in the area of +90°F for average maximum temperature during the day. As September arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 219 mm to 190 mm. Humidity rises from 78% to 79%. Winds are calmer in comparison to August, going down from 1 m/s to 0 m/s on average. The amount of sunny days stay about the same, averaging 0 sunny days during the month.
October brings much the same weather, it remains ok.
Wind
The average wind speed is 1 m/s getting up to 2 m/s which is a light breeze; barely moving the tree leaves.
The average wind speed in Chiang Mai is gradually increasing during September, going from 1 m/s to 2 m/s over the course of the month.
Rain
How was the weather last September in Chiang Mai?
Climate Change Over the Years
The climate in Chiang Mai in September has not changed that much over the last 43 years.
The average temperature was the lowest in 2011 (+88°F) and the highest in 1998 (+93°F). The driest year was 1998 with only 604 mm of rainfall, and the wettest year was 1994 with 1462 mm.
FAQ
Is September a good time to visit Chiang Mai?
Can you sunbathe in Chiang Mai in September?
Is Chiang Mai rainy in September?
Is it sunny in Chiang Mai in September?
Other cities in Thailand
Monthly weather in Chiang Mai
Source of the data
For this page, we’ve looked at the typical weather in Chiang Mai, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.