The climate in Vientiane during September can be summarized as hot, humid and very wet.
September is in the fall / autumn in Vientiane and is typically the 6th warmest month of the year. Daytime maximum temperatures average around a steamy 32°C (89°F), whilst at night 24°C (75°F) is normal.
|Daytime temperature||31.7°C 89°F|
|Nightly temperature||24°C 75.1°F|
|Average temperature||27.8°C 82°F|
|Daily sunshine||5.4 hrs|
|Avg rainfall||278 mm 10.9 ins|
|Rainy days||20 days|
|Sea temperature||29.1°C 84.3°F|
|Windspeed||4.3kph 3 mph|
On average September is the 2nd wettest month of the year in Vientiane with around 278mm 10.9 inches of rain making it a very wet time to visit. This rainfall is typically spread over 20 days, although this may vary considerably.
On the flip side this corresponds to an average of 5.4 hours of sunshine per day.
The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in September 2020.
|Hottest month:||April||35.5°C 95.9°F|
|Driest month:||December||4mm 0.2ins|
|Coldest month:||December||28.3°C 82.9°F|
|Wettest month:||August||332mm 13.1ins|