Bangkok Weather in September
Planning a trip to Bangkok in September? Here's what the weather is really like as monsoon season peaks — and one alert to plan around.
September in Bangkok is hot, humid, and very wet. Highs range from the mid-80s to low 90s°F, lows sit in the mid to upper 70s, and persistent humidity adds bite to the heat. It's not the hottest month, but the rain is the bigger story: September is the wettest month of the year with 16–18 days of rain on average, and Bangkok can pick up a foot of rain across the month.
Flooding is common, monsoon is very busy, and decaying typhoons can push extra moisture into the region and crank out heavy rain. Street flooding can happen, so plan for it with an umbrella, rain gear, and shoes that can handle water. Meteorologist Ian Schwartz breaks down what to expect.
At a glance
What's covered
- Highs, lows, and persistent humidity
- Why September is the wettest month of the year
- How much rain the city can pick up
- Decaying typhoons and enhanced monsoon rain
- Flood potential and street flooding
- What to pack for rain gear
Jump to a moment
Bangkok in September FAQ
What is the weather like in Bangkok in September?
Hot, humid, and very wet. Highs range from the mid-80s to low 90s°F, lows sit in the mid to upper 70s. September is the wettest month of the year in Bangkok — 16–18 days of rain on average, and the city can pick up a foot of total rainfall across the month.
How bad is flooding in Bangkok in September?
Real. Street flooding is common during and after heavy monsoon rains, especially in low-lying neighborhoods. It usually recedes within hours, but can snarl traffic and make some areas hard to reach. Waterproof shoes and building extra transit time into your day are the practical fixes.
Should I avoid Bangkok in September?
Depends on your tolerance for rain. If you want dry sunny days, September is the worst month to pick — go December through February instead. If you can plan around daily afternoon storms and are OK with some flood risk, September offers thinner crowds and lower prices, with the city looking its lushest and greenest.