Sơn Tây in Fall
In fall (September, October and November), Sơn Tây sees average daytime highs around 29°C and overnight lows near 23°C, with 348 mm of rain over about 35 wet days across the season. It is the 2nd-warmest season and the 2nd-wettest season.
Over the season highs ease from about 32°C in early September to 24°C by late November. The sky is clear or mostly clear about 29% of the time across fall, and the air most often feels miserable.
Fall is Sơn Tây's 2nd-best season to visit on our travel score. For the whole year in context, see Sơn Tây's year-round climate.
- Avg daytime high
- 29°C
- 2nd-warmest season
- Avg overnight low
- 23°C
- Rainfall
- 348 mm
- 35 wet days
- Avg wind
- 5 km/h
- Travel score
- 5.3
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in Sơn Tây in Fall
Over the season highs ease from about 32°C in early September to 24°C by late November.
A typical fall day in Sơn Tây reaches about 29°C and drops to 23°C overnight. The warmest of the three months is September, the coolest November.
How fall really feels in Sơn Tây
Once humidity and wind are folded in, fall brings about 47 days that feel above 32°C and 0 that feel at or below 0°C.
The story in fall is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
Sơn Tây weather by month
How the three fall months (September, October and November) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|
| Jan | 20° / 15° | 37 | 8.3 | 10.9 | 6.2 |
| Feb | 22° / 16° | 26 | 7.9 | 11.3 | 6.5 |
| Mar | 25° / 19° | 48 | 10.4 | 11.9 | 6.4 |
| Apr | 29° / 22° | 81 | 10.7 | 12.5 | 5.2 |
| May | 32° / 25° | 201 | 17.4 | 13 | 3.2 |
| Jun | 33° / 27° | 215 | 18.2 | 13.3 | 2.4 |
| Jul | 33° / 27° | 251 | 20.5 | 13.2 | 2.4 |
| Aug | 33° / 26° | 311 | 22.1 | 12.7 | 2.5 |
| Sep | 32° / 25° | 201 | 17.9 | 12.1 | 3.3 |
| Oct | 29° / 23° | 100 | 10.5 | 11.5 | 5.4 |
| Nov | 26° / 19° | 48 | 6.7 | 11 | 7.2 |
| Dec | 22° / 16° | 29 | 6.5 | 10.7 | 7.1 |
Cloud cover in Fall
The sky is clear or mostly clear about 29% of the time across fall.
Chance of precipitation in Fall
Sơn Tây gets around 348 mm of rain over 35 wet days across fall. The line is the day-by-day chance of measurable precipitation.
Humidity in Fall
Most of fall feels miserable — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Fall
Winds average 5 km/h across fall.
Sunrise & sunset in Fall
Daylight runs from about 12 h 24 min in early September to 10 h 48 min by late November. The lit band spans sunrise to sunset each day.
Solar energy in Fall
Average shortwave solar energy reaching the ground each day across fall, about 3.8 kWh/m².
Hazard calendar for Sơn Tây
In fall, Sơn Tây overlaps its pacific typhoon and monsoon season. The full year is below, with each hazard's peak months called out.
Sơn Tây sits in the Pacific typhoon belt; the season peaks July–October.
Sơn Tây's monsoon runs May–September, when most of the year's rain falls.
Is fall a good time to visit Sơn Tây?
Our two travel scores rate fall for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
fall is a reasonable time to visit Sơn Tây for sightseeing. The water and warmth also suit a beach or pool day.
What to pack for Sơn Tây in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Sơn Tây sees daytime highs around 29°C and nights near 23°C. Pack light clothes and rain gear. About 35 days see rain.
UV index in Sơn Tây in Fall
Clear-sky midday UV across fall averages around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Sơn Tây peaks around June 20 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near November 21 at about 6 (high).
The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 6 | 7 | 9 | 6 | 7 | 11 | 10 | 9 | 7 | 8 | 6 | 6 |
| Level | High | High | Very high | High | Very high | Extreme | Extreme | Very high | High | Very high | High | High |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 6 | High |
| Feb | 7 | High |
| Mar | 9 | Very high |
| Apr | 6 | High |
| May | 7 | Very high |
| Jun | 11 | Extreme |
| Jul | 10 | Extreme |
| Aug | 9 | Very high |
| Sep | 7 | High |
| Oct | 8 | Very high |
| Nov | 6 | High |
| Dec | 6 | High |
Air quality in Sơn Tây in Fall
Average fine-particle pollution (PM2.5) through the year — so you can see where fall falls, not just the annual average.
Air quality in Sơn Tây is worst in December — around 171 µg/m³ PM2.5 (very unhealthy), about 3.4× the cleanest month (July, 50 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 161 | 136 | 122 | 106 | 76 | 59 | 50 | 68 | 96 | 125 | 152 | 171 |
| Level | Very unhealthy | Unhealthy | Unhealthy | Unhealthy | Unhealthy | Unhealthy | Poor | Unhealthy | Unhealthy | Unhealthy | Very unhealthy | Very unhealthy |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 161 | Very unhealthy |
| Feb | 136 | Unhealthy |
| Mar | 122 | Unhealthy |
| Apr | 106 | Unhealthy |
| May | 76 | Unhealthy |
| Jun | 59 | Unhealthy |
| Jul | 50 | Poor |
| Aug | 68 | Unhealthy |
| Sep | 96 | Unhealthy |
| Oct | 125 | Unhealthy |
| Nov | 152 | Very unhealthy |
| Dec | 171 | Very unhealthy |
Where is Sơn Tây?
Sơn Tây sits at 21.1°N, 105.5°E, 16 m above sea level, in Vietnam. The nearest listed city is Ba Vì, 14 km away.
Topography around Sơn Tây
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Sơn Tây.
Within 3 km, the terrain around Sơn Tây has only modest variations in elevation — a maximum elevation change of 32 m around an average of 13 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 694 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,677 m.
The land around Sơn Tây is covered by trees (42%), artificial surfaces (22%) and cropland (21%) within 3 km, trees (44%) and cropland (33%) within 16 km, and trees (66%) and cropland (22%) within 80 km.
Vietnam travel facts
- Travel advisory
- Level 1
- Exercise Normal Precautions
- Power plugs
- Type A / B / C / F
- 220 V · 50 Hz
- Prices
- ≈ 29% of US
- price level, 2025
- GDP per capita
- $5,066
- 2025
- Happiness
- 6.4 / 10
- World Happiness, 2025
- Safe drinking water
- 59%
- of population, 2024
- Homicide rate
- 1.5
- per 100k, 2011
- Road deaths
- 30.6
- per 100k/yr, 2019
- Income group
- Upper middle
- World Bank
- English
- Moderate
- EF EPI 500
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Sơn Tây (21.1405°, 105.5069°, elevation 16 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.