Climate averages 1991–2020
Sơn Tây weather
in September.
A hot, very wet month: the 5th warmest and the joint 8th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a hot month in Sơn Tây: daytime highs average 30.0°C and nights cool to about 24.2°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 201 mm of rain on roughly 18 days, which makes September a very wet month (the joint 8th 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 Ba Vì (14 km away). In September its highs average 27.9°C, 2.1°C cooler than Sơn Tây, with 236 mm of rain.
Among the 136 cities listed in Vietnam, Sơn Tây ranks joint 65th of 136 for the warmest September highs and joint 13th of 136 for the driest September (rainfall, lowest first). The mean September high of those 136 cities is 29.7°C; Sơn Tây is 0.3°C warmer than that mean.
From September to October, average highs fall by 2.2°C to 27.8°C, and monthly rainfall falls from 201 mm to 100 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 Tây climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 19.4°C14.0°C | 14.0°C | 37 | 8.3 | 11.011 h |
| February | 21.6°C15.6°C | 15.6°C | 26 | 8.0 | 11.411 h |
| March | 24.9°C18.5°C | 18.5°C | 48 | 10.4 | 12.012 h |
| April | 28.9°C21.8°C | 21.8°C | 81 | 10.7 | 12.613 h |
| May | 31.1°C24.3°C | 24.3°C | 201 | 17.4 | 13.113 h |
| June | 32.3°C25.9°C | 25.9°C | 215 | 18.2 | 13.413 h |
| July | 31.9°C25.9°C | 25.9°C | 251 | 20.5 | 13.313 h |
| August | 31.2°C25.4°C | 25.4°C | 311 | 22.0 | 12.913 h |
| September, selected | 30.0°C24.2°C | 24.2°C | 201 | 17.8 | 12.312 h |
| October | 27.8°C21.9°C | 21.9°C | 100 | 10.5 | 11.712 h |
| November | 24.6°C18.5°C | 18.5°C | 48 | 6.7 | 11.111 h |
| December | 20.6°C14.7°C | 14.7°C | 29 | 6.5 | 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
- Ba Vì in SeptemberVietnam · 14 kmHigh 27.9°C · Low 22.2°C · 236 mm rain
- Vĩnh Yên in SeptemberVietnam · 21 kmHigh 30.4°C · Low 24.3°C · 201 mm rain
- Việt Trì in SeptemberVietnam · 23 kmHigh 30.1°C · Low 24.2°C · 201 mm rain
- Phúc Yên in SeptemberVietnam · 23 kmHigh 30.3°C · Low 24.1°C · 229 mm rain
- Bắc Từ Liêm in SeptemberVietnam · 26 kmHigh 30.2°C · Low 24.0°C · 226 mm rain
- Tây Hồ in SeptemberVietnam · 32 kmHigh 30.3°C · Low 24.1°C · 226 mm rain
- Hanoi in SeptemberVietnam · 37 kmHigh 30.3°C · Low 24.1°C · 226 mm rain
- Sóc Sơn in SeptemberVietnam · 38 kmHigh 30.4°C · Low 24.1°C · 229 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 Tây) is explained once on the Sơn Tây year overview and on the Sources, method and limits page.
Việt Trì and Vĩnh Yên lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.