Climate averages 1991–2020
Vientiane weather
by month.
See how the year changes. April has the highest average daily maximum; December has the lowest average monthly rainfall.
Pleasant-weather months by our simple rule: JanuaryNovemberDecember
Long-term climate patterns, not a forecast for a particular trip.
Across the year Vientiane averages a daytime high of 30.0°C and a nighttime low of 22.0°C, with about 1,919 mm of rain on roughly 165 days. April is the warmest month (average high 33.8°C) and December the coolest (26.9°C). August is the wettest month with 401 mm; December is the driest with 8.4 mm.
Months with pleasant weather by a simple rule (average high between 18°C and 29°C, average low of at least 5°C and at most 8 rain days): January, November and December. This looks at temperature and rain only, not humidity, wind, sea temperature or crowds.
The annual picture
A year in Vientiane
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
Vientiane climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 27.3°C17.0°C | 17.0°C | 11 | 1.8 | 11.211 h |
| February | 29.8°C18.9°C | 18.9°C | 15 | 2.2 | 11.512 h |
| March | 32.6°C22.1°C | 22.1°C | 36 | 6.2 | 12.012 h |
| April | 33.8°C24.4°C | 24.4°C | 75 | 11.9 | 12.513 h |
| May | 31.9°C24.7°C | 24.7°C | 261 | 23.4 | 13.013 h |
| June | 30.5°C24.7°C | 24.7°C | 316 | 25.0 | 13.213 h |
| July | 29.9°C24.4°C | 24.4°C | 372 | 26.5 | 13.113 h |
| August | 29.6°C24.1°C | 24.1°C | 401 | 27.4 | 12.713 h |
| September | 29.6°C23.8°C | 23.8°C | 300 | 24.7 | 12.312 h |
| October | 29.3°C22.7°C | 22.7°C | 101 | 11.9 | 11.712 h |
| November | 28.7°C20.2°C | 20.2°C | 22 | 3.0 | 11.311 h |
| December | 26.9°C17.3°C | 17.3°C | 8.4 | 1.2 | 11.111 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
Nearby cities
- Udon ThaniThailand · 64 kmHigh 30.5°C · Low 22.1°C · 1,542 mm rain a year
- Khon KaenThailand · 171 kmHigh 31.3°C · Low 22.7°C · 1,149 mm rain a year
- Sakon NakhonThailand · 187 kmHigh 30.4°C · Low 22.1°C · 1,642 mm rain a year
- ThakhèkLaos · 244 kmHigh 30.0°C · Low 21.2°C · 2,189 mm rain a year
- SavannakhetLaos · 277 kmHigh 30.3°C · Low 22.0°C · 1,478 mm rain a year
- LampangThailand · 330 kmHigh 30.7°C · Low 22.0°C · 1,328 mm rain a year
- VinhVietnam · 336 kmHigh 27.7°C · Low 22.3°C · 1,510 mm rain a year
- Nakhon RatchasimaThailand · 337 kmHigh 31.6°C · Low 22.8°C · 1,071 mm rain a year
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 limitsWhat do the high and low temperatures mean?
We average the daily maximum and daily minimum for each calendar month over 1991–2020. They are not record extremes, a forecast range or temperatures at a fixed time of day.
How is a rain day counted?
A local calendar day (standard time, UTC+7, no daylight saving) with at least 1 mm of total precipitation counts as one rain day. We count these for each year and month, then average across 30 years. The average does not predict which days will be wet.
Where do the numbers come from?
ERA5-Land (temperature) and ERA5 (precipitation) reanalysis from the Copernicus Climate Change Service, read from the Open-Meteo open-data archive. Temperature comes from the 0.1° model cell at 18.00°, 102.60° (4 km from the city centre), adjusted up by 0.1°C for the difference between the city's elevation (174 m) and the cell's (189 m). Rain comes from the 0.25° cell at 18.00°, 102.50°. These are model estimates, not weather-station readings; coast, hills and city streets can differ.
Does this page show sunshine, humidity or sea temperature?
No. The data used here contain air temperature and precipitation only. Daylight hours are calculated from the city's latitude (sunrise to sunset), not measured sunshine.