Seoul Weather in September
What's the weather like in Seoul (Seoul) in September 2025?
The climate in Seoul during September can be summarized as warm, humid and wet.
September is in the fall / autumn in Seoul and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a muggy 26°C (78°F), whilst at night 16°C (61°F) is normal.
| Daytime temperature | 25.6°C 78°F |
|---|---|
| Nightly temperature | 16.1°C 60.9°F |
| Average temperature | 20.8°C 69.4°F |
| Daily sunshine | 7.2 hrs |
| Avg rainfall | 161 mm 6.3 ins |
| Rainy days | 9 days |
| Sea temperature | 23.2°C 73.8°F |
| Humidity | 75% |
| Windspeed | 6.1kph 4 mph |
On average September is the 3rd wettest month of the year in Seoul with around 161mm 6.3 inches of rain making it a wet time to visit. This rainfall is typically spread over 9 days, although this may vary considerably.
On the flip side this corresponds to an average of 7.2 hours of sunshine per day.
September temperatures in Seoul
September rainfall
September hourly sunshine
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 Seoul in September 2025.
Other monthly averages
Best places to visit in September
Seoul weather stats
| Hottest month: | August | 29.2°C 84.6°F |
|---|---|---|
| Driest month: | December | 21mm 0.8ins |
| Sunniest month: | October | 7.3hrs |
| Coldest month: | January | 0.9°C 33.6°F |
| Wettest month: | July | 358mm 14.1ins |
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