Chiang Rai weather in September
September in Chiang Rai: hot, soaked, with clean air — a gamble, with 24 rainy days.
#10 of 12 months in Chiang Rai · #825 of 897 destinations to visit in September · comfort 56/100 (tier D)
Updated June 2026 · climate normals from ERA5 reanalysis
Traveller notes on Chiang Rai in September
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Chiang Rai climate normals — September
| Daytime high | 30°C / 86°F | 🥵 hot |
|---|---|---|
| Nighttime low | 23°C / 74°F | |
| Rainfall | 258 mm / 10.2 in | ⛈ soaked |
| Rainy days | 24 days | |
| Humidity | 86% | 💦 very humid |
| Dew point | 23°C / 74°F | |
| Sunshine | 9 h/day | |
| Daylight | 12.2 h | |
| Wind | 7 km/h / 4 mph | |
| Air quality (US AQI) | 38 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
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Chiang Rai in September — FAQ
- Is September a good time to visit Chiang Rai?
- September in Chiang Rai: hot, soaked, with clean air — a gamble, with 24 rainy days. It ranks #10 of 12 months for Chiang Rai on SeasonMap's comfort score (56/100).
- What is the weather like in Chiang Rai in September?
- In September, Chiang Rai averages a daily high of 29.8°C and a low of 23.3°C, with about 257.9 mm of rain over roughly 24.2 rainy days.
- What is the air quality in Chiang Rai in September?
- Chiang Rai has a mean US Air Quality Index of about 38 in September.