Vientiane weather in September
Temperature, rain and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Fair
Best time to visit: November – January
What is the weather like in Vientiane in September?
In September, Vientiane is hot: daytime highs average 30 °C, and even at night it stays warm at around 24 °C. Expect around 5 hours of sunshine a day. It is the rainy season: rain falls on about 24 days, totalling 312 mm. On about 14 days the thermometer climbs to 30 °C or more. The air is often humid and muggy. All in all, September is a so-so month for a holiday in Vientiane.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 36 | 41 | 61 |
| Day | 30° | 30° | 30° |
| Night | 24° | 24° | 23° |
| Sun | 4 h | 5 h | 7 h |
| Rain days | 28 | 24 | 12 |
More details for September
- Daylight
- 12 h 16 min05:57 – 18:13
- UV index
- 12 · extremeclear sky, noon (estimate)All months
- Muggy days
- 30 daysdew point 18 °C or moreAll months
- Wind
- 8 km/haverage daily peakAll months
- Cloud cover
- 81 %on averageAll months
- Hot days
- 14 days30 °C or moreAll months
- Time zone
- UTC+7Asia/Vientiane
How the score comes together
- Temperatureweight 50 %66 %
- Sunshineweight 20 %38 %
- Few rainy daysweight 30 %0 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in September
- Sunscreen
- Sunglasses & sun hat
- Light, breathable clothes
- Water bottle – drink plenty
- Insect repellent
- Rain jacket or umbrella
Vientiane in September: quick answers
Is Vientiane hot in September?
Yes. In September, Vientiane is hot: daytime highs average 30 °C and nights stay around 24 °C. On about 14 days the thermometer climbs to 30 °C or more.
Does it rain much in Vientiane in September?
It rains often – on about 24 days, adding up to 312 mm.
Vientiane month by month
The whole year in VientianeAll destinations: LaosWhere to go in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences