Weather in Vientiane in September 2025
Average weather
Average temperature in Vientiane in September
The temperature in September is +90°F on average, with a range between a maximum of +95°F during the day and a minimum of +75°F at night.
The average maximum temperature goes down 27% by the end of the month, compared with the beginning of the month, from +93°F to +88°F.
Is Vientiane warm or cold in September?
Vientiane is typically hot in September.
Maximum temperatures go up compared to the previous month from +88°F to +88°F. The minimum temperature also goes up from +77°F to +77°F.
Make sure that you pack your summer linen and swimming costumes; it’s probably going to be hot.
Take a look at how September is compared to other months in Vientiane:
Climate in Vientiane in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +88°F | +88°F | +88°F | ||||
| Min. temperature | ||||||
| +73°F | +70°F | +59°F | ||||
| Max. temperature | ||||||
| +99°F | +97°F | +97°F | ||||
| Rainfall | ||||||
| 373 mm | 282 mm | 95 mm | ||||
| Wind | ||||||
| 1 m/s | 0 m/s | 0 m/s | ||||
| Humidity | ||||||
| 84% | 83% | 79% | ||||
| Air pressure | ||||||
| 1005 HPa | 1007 HPa | 1010 HPa | ||||
| Sunny days | ||||||
| 0 | 0 | 4 | ||||
| Cloudy days | ||||||
| 1 | 2 | 9 | ||||
| Rainy days | ||||||
| 27 | 24 | 17 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
September weather is still as ok as in August. The temperature levels stay the same in the area of +88°F for average maximum temperature during the day. As September arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 373 mm to 282 mm. It feels drier, as humidity decreases from 84% to 83%. Winds are calmer in comparison to August, going down from 1 m/s to 0 m/s on average. The amount of sunny days stay about the same, averaging 0 sunny days during the month.
October brings much the same weather, it remains ok.
Wind
The average wind speed is 1 m/s getting up to 3 m/s which is a light breeze; barely moving the tree leaves.
The average wind speed in Vientiane is gradually decreasing during September, going from 1 m/s to 0 m/s over the course of the month.
Rain
How was the weather last September in Vientiane?
Climate Change Over the Years
The climate in Vientiane in September has not changed that much over the last 43 years.
The average temperature was the lowest in 1996 (+87°F) and the highest in 2019 (+92°F). The driest year was 2019 with only 1054 mm of rainfall, and the wettest year was 1994 with 2326 mm.
FAQ
Is September a good time to visit Vientiane?
Can you sunbathe in Vientiane in September?
Is Vientiane rainy in September?
Is it sunny in Vientiane in September?
Other cities in Laos
Monthly weather in Vientiane
Source of the data
For this page, we’ve looked at the typical weather in Vientiane, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.
