Seongnam Weather in September
What's the weather like in Seongnam (Gyeonggi Province) in September 2025?
The climate in Seongnam during September can be summarized as warm, humid and wet.
September is in the fall / autumn in Seongnam and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a muggy 25°C (78°F), whilst at night 15°C (59°F) is normal.
| Daytime temperature | 25.3°C 77.5°F |
|---|---|
| Nightly temperature | 15°C 58.9°F |
| Average temperature | 20.1°C 68.2°F |
| Daily sunshine | 7.3 hrs |
| Avg rainfall | 155 mm 6.1 ins |
| Rainy days | 9 days |
| Sea temperature | 22.9°C 73.3°F |
| Humidity | 77% |
| Windspeed | 5.4kph 3 mph |
On average September is the 3rd wettest month of the year in Seongnam with around 155mm 6.1 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 7.3 hours of sunshine per day.
September temperatures in Seongnam
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 Seongnam in September 2025.
Other monthly averages
Best places to visit in September
Seongnam weather stats
| Hottest month: | August | 29.2°C 84.6°F |
|---|---|---|
| Driest month: | December | 22mm 0.9ins |
| Sunniest month: | October | 7.4hrs |
| Coldest month: | January | 0.6°C 33.1°F |
| Wettest month: | July | 349mm 13.7ins |
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