Vieng Xai in Summer
In summer (June, July and August), Vieng Xai sees average daytime highs around 29°C and overnight lows near 21°C, with 768 mm of rain over about 77 wet days across the season. It is the warmest season of the year and the wettest season of the year.
Across summer, daytime highs hold fairly steady around 29°C. The sky is clear or mostly clear about 3% of the time across summer, and the air most often feels oppressive.
Summer is Vieng Xai's weakest season of the year to visit on our travel score. For the whole year in context, see Vieng Xai's year-round climate.
- Avg daytime high
- 29°C
- warmest season of the year
- Avg overnight low
- 21°C
- Rainfall
- 768 mm
- 77 wet days
- Avg wind
- 5 km/h
- Travel score
- 3.4
- weakest season of the year
- Months
- Jun · Jul · Aug
Temperature in Vieng Xai in Summer
Across summer, daytime highs hold fairly steady around 29°C.
A typical summer day in Vieng Xai reaches about 29°C and drops to 21°C overnight. The warmest of the three months is June, the coolest August.
How summer really feels in Vieng Xai
Once humidity and wind are folded in, summer brings about 24 days that feel above 32°C and 0 that feel at or below 0°C.
The story in summer is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
Vieng Xai weather by month
How the three summer months (June, July and August) 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 Summer
The sky is clear or mostly clear about 3% of the time across summer.
Chance of precipitation in Summer
Vieng Xai gets around 768 mm of rain over 77 wet days across summer. The line is the day-by-day chance of measurable precipitation.
Humidity in Summer
Most of summer feels oppressive — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Summer
Winds average 5 km/h across summer.
Sunrise & sunset in Summer
Daylight runs from about 13 h 06 min in early June to 12 h 24 min by late August. The lit band spans sunrise to sunset each day.
Solar energy in Summer
Average shortwave solar energy reaching the ground each day across summer, about 4.6 kWh/m².
Hazard calendar for Vieng Xai
In summer, 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 summer a good time to visit Vieng Xai?
Our two travel scores rate summer for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
summer is a weaker month for outdoor sightseeing in Vieng Xai.
What to pack for Vieng Xai in Summer
From summer's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In summer, Vieng Xai sees daytime highs around 29°C and nights near 21°C. Pack light clothes and rain gear. Worth having: sun protection. About 77 days see rain.
UV index in Vieng Xai in Summer
Clear-sky midday UV across summer averages around 13 (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 Summer
Average fine-particle pollution (PM2.5) through the year — so you can see where summer 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.