Vientiane Weather in September

September in Vientiane brings very high temperatures, with daytime highs of 33°C (91°F) and nights around 25°C (77°F). It's part of the rainy season, with 309 mm (12 in) of rainfall on average, so an umbrella or poncho is a good idea.

Rainfall in Vientiane in September

As part of the rainy season, Vientiane sees around 20 days of rain in September, with an average of 309 mm (12 in). The rain this month falls heavily when it arrives. Late afternoons in particular can see strong showers, so waterproofs are worth keeping handy.

Temperature in Vientiane in September

Daytime highs in Vientiane in September reach 33°C (91°F), with nights around 25°C (77°F). It's usually most comfortable outside during the morning and later in the day. With lows around 25°C (77°F), the nights are warm enough that a sheet is usually all you need for bedding.

Sunshine in Vientiane in September

You can expect a moderate amount of sunlight, with approximately 168 hours. Even though this month is part of the wet season, you can still see the sun occasionally.

Wind Speed in Vientiane in September

September has wind speeds averaging 1 m/s (2 knots). You can expect very gentle conditions with light air movement on typical days. Since this is an average, daily weather varies from perfectly still moments to some breezier days.

September in Vientiane has its charm. However, if you're seeking pleasant, dry and sunny weather, our weather planner can help you explore other destinations in the world.

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For a detailed overview over the year and the best time to visit Laos, check out our Vientiane's climate page.

Vientiane Temperature in September

Min Temperature 25°C (77°F)  

Max Temperature 33°C (91°F)  

Chance of Rain 66%  

Precipitation 309 mm (12 in)  

Rainy days 20 days  

Humidity 83%  

Windspeed 1 m/s (2 knots)  

Sunshine 168 hours  

Percentage Sunshine  

Daily Historical Temperatures

50-year average (1976-2025)

Based on our historical records, temperatures in Vientiane typically stay consistent throughout September, with daily highs averaging around 33°C (91°F). Nights are warm, with lows around 25°C (77°F).

Average temperatures in September

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Daily Historical Precipitation

50-year average (1976-2025)

Average daily rainfall for each day of the month based on long-term records.

Average precipitation in September

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Historical weather for Vientiane in September

Browse day-by-day weather records for Vientiane spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.

Historical weather Temperatures Precipitation

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Vientiane historical weather extremes in September

Based on 49 years of weather observations (1976-2025), these are the most extreme conditions recorded in Vientiane.

• The warmest day in September was on September 23, 1981, with a maximum of 39°C (102°F).
• The coldest September day was on September 10, 2004, with a maximum of 25°C (77°F).
• Nighttime temperatures dropped to 21°C (70°F) on September 25, 2019, marking the coldest September night on record.
• Peak precipitation in September occurred on September 2, 2014, when 173 mm (6.8 in) of precipitation was measured.

What to Wear in Vientiane in September

Warm but pleasant conditions in Vientiane in September. Focus on lightweight, maybe with natural fabrics, cotton blend shirts, comfortable shorts, and breathable footwear. A light cover-up for sun protection is smart too. It's going to pour! Pack a good poncho and prepare for very wet conditions. Bring sunglasses since you'll have some sunny periods throughout the month

What To Do in Vientiane in September

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Swimming

7/10

Cycling

7/10

Walking

7/10

Camping

7/10

Outdoor sports

7/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit Laos, check out our Vientiane's climate page.

More climate data for Vientiane

Temperature Rainfall Sunshine Humidity Wind Speed

See the full Vientiane climate overview or explore weather in Laos.