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The weather in Seoul in September is hot. The average temperatures are between 20°C and 26°C.
You can expect about 3 to 8 days of rain in Seoul during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Seoul in September 2025.
If you’re planning to visit Seoul in the near future, we highly recommend that you review the 14 day weather forecast for Seoul before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 1° / -4° | 4 | 19 | 8 | 25 mm | Awful | Seoul in January |
| February | 4° / -1° | 2 | 22 | 4 | 35 mm | Awful | Seoul in February |
| March | 10° / 4° | 3 | 26 | 2 | 59 mm | Bad | Seoul in March |
| April | 15° / 9° | 5 | 25 | 0 | 83 mm | Good | Seoul in April |
| May | 21° / 14° | 5 | 26 | 0 | 119 mm | Good | Seoul in May |
| June | 25° / 19° | 5 | 25 | 0 | 138 mm | Perfect | Seoul in June |
| July | 28° / 23° | 11 | 20 | 0 | 438 mm | Good | Seoul in July |
| August | 29° / 24° | 10 | 21 | 0 | 325 mm | Ok | Seoul in August |
| September | 26° / 20° | 5 | 25 | 0 | 156 mm | Perfect | Seoul in September |
| October | 20° / 14° | 3 | 28 | 0 | 77 mm | Good | Seoul in October |
| November | 12° / 7° | 4 | 24 | 2 | 86 mm | Bad | Seoul in November |
| December | 3° / -1° | 5 | 18 | 8 | 40 mm | Awful | Seoul in December |