Vientiane
Laos
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Vientiane, Laos

Water geysers around the memorial Patuxay Monument in Vientiane, Laos
Water geysers around the memorial Patuxay Monument in Vientiane, Laos
September, the first month of the autumn, in Vientiane, is also a hot month, with average temperature fluctuating between 24.1°C (75.4°F) and 30.9°C (87.6°F).

Temperature

In Vientiane, the average high-temperature in September is practically the same as in August - a still tropical 30.9°C (87.6°F). The average low-temperature, in Vientiane, is 24.1°C (75.4°F).

Humidity

In September, the average relative humidity is 83%.

Rainfall

In Vientiane, in September, during 17 rainfall days, 297.3mm (11.7") of precipitation is typically accumulated. Throughout the year, in Vientiane, there are 118 rainfall days, and 1660.5mm (65.4") of precipitation is accumulated.

Daylight

In Vientiane, Laos, the average length of the day is 12.2h.

Sunshine

The average sunshine in Vientiane is 4.6h.

UV index

Months with the highest UV index in Vientiane are March through September, with an average maximum UV index of 12. A UV Index estimate of 11, and higher, represents an ultimate health vulnerability from the exposure to the Sun's UV rays for ordinary individuals.
The daily maximum UV index of 12 in September interpret into the following advice:
Take all required precautions, as unprotected skin and eyes can burn in minutes. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. A broad-spectrum sunscreen of SPF 30+ should be liberally applied and re-applied every two hours, and immediately after an outdoor workout or a swim.

What is the temperature in September in Vientiane?

In Vientiane, in September, the average high-temperature is 30.9°C (87.6°F), and the average low-temperature is 24.1°C (75.4°F).

What is the average humidity in September in Vientiane?

In Vientiane, the average relative humidity in September is 83%.

How many days does it rain in September in Vientiane?

In Vientiane, in September, during 17 rainfall days, 297.3mm (11.7") of precipitation is typically accumulated.

What is the average length of the day in September in Vientiane?

The average length of the day in September is 12.2h.

How long on average sun shines in September in Vientiane?

The average sunshine in September in Vientiane is 4.6h.

What is the month with the highest UV index in Vientiane?

Months with the highest UV index are March through September, with an average maximum UV index of 12.

What is the UV index intensity in September in Vientiane?

The average daily maximum UV index in September is 12. A UV Index reading of 11, and higher, represents an ultimate hazard to health from the exposure to the Sun's UV rays.
Average temperature in September - Vientiane, Laos
  • Average high temperature in September: 30.9°C

The warmest month (with the highest average high temperature) is April (34.3°C).
The month with the lowest average high temperature is December (28.1°C).

  • Average low temperature in September: 24.1°C

The month with the highest average low temperature is June (24.9°C).
The coldest month (with the lowest average low temperature) is January (16.4°C).

Average humidity in September - Vientiane, Laos
  • Average humidity in September: 83%

The month with the highest relative humidity is August (84%).
The month with the lowest relative humidity is March (66%).

Average rainfall in September - Vientiane, Laos
  • Average rainfall in September: 297.3mm

The wettest month (with the highest rainfall) is August (334.6mm).
The driest month (with the lowest rainfall) is December (2.5mm).

Average rainfall days in September - Vientiane, Laos
  • Average rainfall days in September: 17 days

The month with the highest number of rainy days is August (21 days).
Months with the lowest number of rainy days are January and December (1 days).

Average daylight in September / Average sunshine in September - Vientiane, Laos
  • Average daylight in September: 12.2h

The month with the longest days is June (Average daylight: 13.2h).
The month with shortest days is December (Average daylight: 11.1h).

  • Average sunshine in September: 4.6h

The month with most sunshine is December (Average sunshine: 8.3h).
The month with least sunshine is August (Average sunshine: 4.4h).

Average UV index in September - Vientiane, Laos
  • Average UV index in September: 12

Months with the highest UV index are March, April, May, June, July, August and September (UV index 12).
The month with the lowest UV index is December (UV index 8).