Weather in Seoul in September 2025
Average weather
Average temperature in Seoul in September
The temperature in September is +27°C on average, with a range between a maximum of +33°C during the day and a minimum of +13°C at night.
The average maximum temperature goes down 30% by the end of the month, compared with the beginning of the month, from +29°C to +23°C.
Is Seoul warm or cold in September?
Seoul is typically warm in September.
Maximum temperatures go down compared to the previous month from +30°C to +26°C. The minimum temperature also goes down from +22°C to +17°C.
It’s generally warm, but pack a long-sleeve shirt for evenings.
Take a look at how September is compared to other months in Seoul:
Climate in Seoul in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +30°C | +26°C | +20°C | ||||
| Min. temperature | ||||||
| +14°C | +5°C | -3°C | ||||
| Max. temperature | ||||||
| +38°C | +33°C | +29°C | ||||
| Rainfall | ||||||
| 223 mm | 117 mm | 47 mm | ||||
| Wind | ||||||
| 2 m/s | 2 m/s | 2 m/s | ||||
| Humidity | ||||||
| 77% | 72% | 68% | ||||
| Air pressure | ||||||
| 1007 HPa | 1013 HPa | 1018 HPa | ||||
| Sunny days | ||||||
| 4 | 10 | 14 | ||||
| Cloudy days | ||||||
| 8 | 9 | 9 | ||||
| Rainy days | ||||||
| 14 | 10 | 7 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
September often has better weather than August. It’s getting colder in September. From +30°C in the day, the average maximum temperature lowers to +26°C. As September arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 223 mm to 117 mm. It feels drier, as humidity decreases from 77% to 72%. The average wind speed doesn’t change much during September, staying around 2 m/s. The good news is there are likely to be more sunny days in September, from 4 to 10.
October brings much the same weather, it remains good.
Wind
The average wind speed is 2 m/s getting up to 3 m/s which is a light breeze; barely moving the tree leaves.
The average wind speed in Seoul is gradually increasing during September, going from 2 m/s to 3 m/s over the course of the month.
Rain
How was the weather last September in Seoul?
Climate Change over Years
The climate in Seoul in September has not changed much over the last 43 years.
The average temperature was the lowest in 1980 (+15°C) and the highest in 2021 (+18°C). The driest year was 2001 with only 618 mm of rainfall, and the wettest year was 2020 with 1720 mm.
FAQ
Is September a good time to visit Seoul?
Can you sunbathe in Seoul in September?
Is Seoul rainy in September?
Is it sunny in Seoul in September?
Other cities in South Korea
Monthly weather in Seoul
Source of the data
For this page, we’ve looked at the typical weather in Seoul, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.