Vieng Xai in Fall
In fall (September, October and November), Vieng Xai sees average daytime highs around 25°C and overnight lows near 17°C, with 315 mm of rain over about 41 wet days across the season. It is the 3rd-warmest season and the 3rd-wettest season.
Over the season highs ease from about 28°C in early September to 21°C by late November. The sky is clear or mostly clear about 19% of the time across fall, and the air most often feels muggy.
Fall is Vieng Xai's 2nd-best season to visit on our travel score. For the whole year in context, see Vieng Xai's year-round climate.
- Avg daytime high
- 25°C
- 3rd-warmest season
- Avg overnight low
- 17°C
- Rainfall
- 315 mm
- 41 wet days
- Avg wind
- 5 km/h
- Travel score
- 6.0
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in Vieng Xai in Fall
Over the season highs ease from about 28°C in early September to 21°C by late November.
A typical fall day in Vieng Xai reaches about 25°C and drops to 17°C overnight. The warmest of the three months is September, the coolest November.
How fall really feels in Vieng Xai
Once humidity and wind are folded in, fall brings about 0 days that feel above 32°C and 0 that feel at or below 0°C.
fall sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.
Vieng Xai 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° / 11° | 22 | 4.4 | 10.9 | 7.0 |
| Feb | 22° / 12° | 14 | 3.8 | 11.3 | 7.6 |
| Mar | 25° / 15° | 60 | 10.6 | 11.9 | 6.8 |
| Apr | 28° / 18° | 109 | 17.7 | 12.5 | 5.1 |
| May | 29° / 20° | 205 | 23.2 | 13 | 3.7 |
| Jun | 29° / 22° | 201 | 24.2 | 13.2 | 3.2 |
| Jul | 29° / 22° | 264 | 26.2 | 13.1 | 3.3 |
| Aug | 28° / 21° | 302 | 26.8 | 12.7 | 3.6 |
| Sep | 27° / 20° | 193 | 20.1 | 12.1 | 4.7 |
| Oct | 25° / 18° | 91 | 14.2 | 11.5 | 6.1 |
| Nov | 23° / 15° | 32 | 6.3 | 11 | 7.3 |
| Dec | 20° / 11° | 19 | 4.2 | 10.8 | 7.1 |
Cloud cover in Fall
The sky is clear or mostly clear about 19% of the time across fall.
Chance of precipitation in Fall
Vieng Xai gets around 315 mm of rain over 41 wet days across fall. The line is the day-by-day chance of measurable precipitation.
Humidity in Fall
Most of fall feels muggy — 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 54 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 3.9 kWh/m².
Hazard calendar for Vieng Xai
In fall, Vieng Xai overlaps its monsoon season. The full year is below, with each hazard's peak months called out.
Vieng Xai's monsoon runs May–September, when most of the year's rain falls.
Is fall a good time to visit Vieng Xai?
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 Vieng Xai for sightseeing.
What to pack for Vieng Xai in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Vieng Xai sees daytime highs around 25°C and nights near 17°C. Pack light clothes and rain gear. About 41 days see rain.
UV index in Vieng Xai in Fall
Clear-sky midday UV across fall averages around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Vieng Xai peaks around August 12 at about 14 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 7 (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) | 8 | 9 | 10 | 9 | 10 | 14 | 13 | 14 | 10 | 9 | 8 | 7 |
| Level | Very high | Very high | Very high | Very high | Extreme | Extreme | Extreme | Extreme | Very high | Very high | Very high | High |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 8 | Very high |
| Feb | 9 | Very high |
| Mar | 10 | Very high |
| Apr | 9 | Very high |
| May | 10 | Extreme |
| Jun | 14 | Extreme |
| Jul | 13 | Extreme |
| Aug | 14 | Extreme |
| Sep | 10 | Very high |
| Oct | 9 | Very high |
| Nov | 8 | Very high |
| Dec | 7 | High |
Air quality in Vieng Xai 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 Vieng Xai is worst in April — around 288 µg/m³ PM2.5 (very unhealthy), about 35.5× the cleanest month (August, 8 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) | 20 | 28 | 98 | 288 | 64 | 14 | 9 | 8 | 11 | 15 | 15 | 19 |
| Level | Moderate | Moderate | Unhealthy | Very unhealthy | Unhealthy | Moderate | Good | Good | Good | Moderate | Moderate | Moderate |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 20 | Moderate |
| Feb | 28 | Moderate |
| Mar | 98 | Unhealthy |
| Apr | 288 | Very unhealthy |
| May | 64 | Unhealthy |
| Jun | 14 | Moderate |
| Jul | 9 | Good |
| Aug | 8 | Good |
| Sep | 11 | Good |
| Oct | 15 | Moderate |
| Nov | 15 | Moderate |
| Dec | 19 | Moderate |
Where is Vieng Xai?
Vieng Xai sits at 20.4°N, 104.2°E, 0 m above sea level, in Laos. The nearest listed city is Xam Nua, 19 km away.
Topography around Vieng Xai
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Vieng Xai.
Within 3 km, the terrain around Vieng Xai has large variations in elevation — a maximum elevation change of 661 m around an average of 915 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,259 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,998 m.
The land around Vieng Xai is covered by trees (65%) and grassland (25%) within 3 km, trees (86%) within 16 km, and trees (82%) within 80 km.
Laos travel facts
- Travel advisory
- Level 2
- Exercise Increased Caution
- Power plugs
- Type A / B / C / E / F
- 230 V · 50 Hz
- Prices
- ≈ 23% of US
- price level, 2025
- GDP per capita
- $2,325
- 2025
- Happiness
- 5.5 / 10
- World Happiness, 2025
- Safe drinking water
- 35%
- of population, 2024
- Road deaths
- 17.9
- per 100k/yr, 2019
- Income group
- Lower middle
- World Bank
- English
- Low
- EF EPI 461
- 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 Vieng Xai (20.4068°, 104.2238°, elevation 0 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.