Climate averages 1991–2020
Sơn La weather
in September.
A warm, wet month: the joint 6th warmest and the 9th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Sơn La: daytime highs average 27.4°C and nights cool to about 20.9°C. By daytime temperature it is the joint 6th warmest of the 12 months.
Expect about 150 mm of rain on roughly 18 days, which makes September a wet month (the 9th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 17 min on an average September day.
The nearest other city in this atlas is Thị Trấn Thuận Châu (27 km away). In September its highs average 27.9°C, about as warm as Sơn La, with 185 mm of rain.
Among the 136 cities listed in Vietnam, Sơn La ranks 127th of 136 for the warmest September highs and 1st of 136 for the driest September (rainfall, lowest first). The mean September high of those 136 cities is 29.7°C; Sơn La is 2.2°C cooler than that mean.
From September to October, average highs fall by 1.5°C to 25.9°C, and monthly rainfall falls from 150 mm to 49 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
Sơn La climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 20.9°C12.3°C | 12.3°C | 24 | 4.0 | 11.011 h |
| February | 23.5°C13.8°C | 13.8°C | 20 | 3.7 | 11.411 h |
| March | 27.4°C16.9°C | 16.9°C | 50 | 7.1 | 12.012 h |
| April | 29.0°C19.5°C | 19.5°C | 72 | 12.7 | 12.613 h |
| May | 29.3°C21.3°C | 21.3°C | 147 | 19.3 | 13.113 h |
| June | 28.7°C22.2°C | 22.2°C | 209 | 23.0 | 13.413 h |
| July | 28.1°C22.1°C | 22.1°C | 288 | 24.5 | 13.313 h |
| August | 28.0°C21.8°C | 21.8°C | 283 | 25.2 | 12.913 h |
| September, selected | 27.4°C20.9°C | 20.9°C | 150 | 17.5 | 12.312 h |
| October | 25.9°C18.8°C | 18.8°C | 49 | 8.3 | 11.712 h |
| November | 23.8°C15.7°C | 15.7°C | 26 | 4.5 | 11.111 h |
| December | 21.0°C12.4°C | 12.4°C | 23 | 3.6 | 10.911 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
- Thị Trấn Thuận Châu in SeptemberVietnam · 27 kmHigh 27.9°C · Low 21.4°C · 185 mm rain
- Dien Bien Phu in SeptemberVietnam · 93 kmHigh 28.3°C · Low 21.8°C · 199 mm rain
- Yên Bái in SeptemberVietnam · 112 kmHigh 29.5°C · Low 24.0°C · 229 mm rain
- Lào Cai in SeptemberVietnam · 129 kmHigh 29.8°C · Low 23.5°C · 165 mm rain
- Phú Thọ in SeptemberVietnam · 135 kmHigh 30.0°C · Low 24.2°C · 225 mm rain
- Tuyên Quang in SeptemberVietnam · 145 kmHigh 30.3°C · Low 24.2°C · 232 mm rain
- Việt Trì in SeptemberVietnam · 154 kmHigh 30.1°C · Low 24.2°C · 201 mm rain
- Ba Vì in SeptemberVietnam · 154 kmHigh 27.9°C · Low 22.2°C · 236 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 Sơn La) is explained once on the Sơn La year overview and on the Sources, method and limits page.