Climate averages 1991–2020
Chiang Rai weather
in September.
A hot, very wet month: the 8th warmest and the 9th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a hot month in Chiang Rai: daytime highs average 29.0°C and nights cool to about 22.9°C. By daytime temperature it is the 8th warmest of the 12 months.
Expect about 295 mm of rain on roughly 25 days, which makes September a very wet month (the 9th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 16 min on an average September day.
The nearest other city in this atlas is Chiang Mai (153 km away). In September its highs average 29.3°C, about as warm as Chiang Rai, with 227 mm of rain.
Among the 46 cities listed in Thailand, Chiang Rai ranks 44th of 46 for the warmest September highs and 42nd of 46 for the driest September (rainfall, lowest first). The mean September high of those 46 cities is 30.3°C; Chiang Rai is 1.3°C cooler than that mean.
From September to October, average highs fall by 0.7°C to 28.4°C, and monthly rainfall falls from 295 mm to 139 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Chiang Rai climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 26.6°C15.0°C | 15.0°C | 22 | 3.0 | 11.111 h |
| February | 30.0°C16.2°C | 16.2°C | 14 | 2.5 | 11.511 h |
| March | 33.0°C19.3°C | 19.3°C | 42 | 5.1 | 12.012 h |
| April | 33.6°C22.4°C | 22.4°C | 132 | 11.8 | 12.613 h |
| May | 31.5°C23.4°C | 23.4°C | 292 | 22.8 | 13.113 h |
| June | 30.4°C23.7°C | 23.7°C | 297 | 26.2 | 13.313 h |
| July | 29.5°C23.4°C | 23.4°C | 398 | 28.4 | 13.213 h |
| August | 29.2°C23.2°C | 23.2°C | 383 | 28.8 | 12.813 h |
| September, selected | 29.0°C22.9°C | 22.9°C | 295 | 25.1 | 12.312 h |
| October | 28.4°C21.6°C | 21.6°C | 139 | 17.8 | 11.712 h |
| November | 27.2°C18.4°C | 18.4°C | 49 | 6.6 | 11.211 h |
| December | 25.5°C15.4°C | 15.4°C | 27 | 3.7 | 11.011 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Chiang Mai in SeptemberThailand · 153 kmHigh 29.3°C · Low 22.9°C · 227 mm rain
- Lampang in SeptemberThailand · 183 kmHigh 29.1°C · Low 23.3°C · 256 mm rain
- Kēng Tung in SeptemberMyanmar · 192 kmHigh 28.2°C · Low 21.1°C · 180 mm rain
- Möng Yang in SeptemberMyanmar · 216 kmHigh 26.8°C · Low 19.6°C · 163 mm rain
- Yunjinghong in SeptemberChina · 255 kmHigh 29.1°C · Low 21.8°C · 192 mm rain
- Menglang in SeptemberChina · 295 kmHigh 26.5°C · Low 19.2°C · 160 mm rain
- Taunggyi in SeptemberMyanmar · 307 kmHigh 23.5°C · Low 17.0°C · 159 mm rain
- Yawnghwe in SeptemberMyanmar · 314 kmHigh 26.6°C · Low 20.1°C · 159 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Chiang Rai) is explained once on the Chiang Rai year overview and on the Sources, method and limits page.