What is the weather like in Chiang Mai vs Ko Samui in September?

In September, Chiang Mai averages 33°C high / 24°C low with about 232 mm of rain; Ko Samui averages 32°C high / 25°C low with about 141 mm.

Chiang Mai vs Ko Samui in September

Ko Samui is the better pick in September — 73 vs 49 on SeasonMap's comfort score. Ko Samui is sweltering, rainy, clean air, while Chiang Mai is sweltering, soaked, muggy air.

Chiang Mai vs Ko Samui — September climate, side by side

	Chiang Mai	Ko Samui
Comfort score	49/100 (F)	73/100 (B)
Feels-like high	39°C	37°C
Avg high / low	33° / 24°	32° / 25°
Rainfall	232 mm	141 mm
Rainy days	23	22
Humidity	86%	79%
Air quality (AQI)	53	27

Monthly climate normals (ERA5 reanalysis). Comfort scores are SeasonMap estimates.

Chiang Mai vs Ko Samui in September — FAQ

Is September better in Chiang Mai or Ko Samui?: Ko Samui is the better pick in September — 73 vs 49 on SeasonMap's comfort score. Ko Samui is sweltering, rainy, clean air, while Chiang Mai is sweltering, soaked, muggy air.
What is the weather like in Chiang Mai vs Ko Samui in September?: In September, Chiang Mai averages 33°C high / 24°C low with about 232 mm of rain; Ko Samui averages 32°C high / 25°C low with about 141 mm.