Early autumn · Weather & things to do
Seoul in September
Seoul cools off: highs slip to 76°F (25°C), from 83°F in August, with lows of 62°F (17°C) and about 5.4 in (138 mm) of rain.
Our comfort score puts it mid-table at 73/100, 5th of 12.
- Avg high
- 76°F (25°C)
- Avg low
- 62°F (17°C)
- Rain
- 5.4 in (138 mm)
- Humidity
- 79%
- Cloud cover
- 57%
- Daylight
- ~12 h 14 min
- Comfort score
- 73/100 · Good
What September feels like
Highs settle around 76°F (25°C), warm enough for short sleeves.
Nights cool to an average low of 62°F (17°C).
Humidity averages 79%, so the air feels sticky and the heat feels stronger than the thermometer says.
Expect regular rain: about 5.4 in (138 mm) falls in the month.
Plan around September
September sits mid-table; the best months are May and October.
- Last warm month for a while: October highs fall to 65°F.
- Inside the wettest three-month stretch, July – September.
- Comfort improves from 48/100 in August to 73/100.
- September sits inside the Apr – Jun, Sep – Nov window our Seoul, Gyeongju & Busan route recommends.
What to pack for September
- Light, breathable clothes76°F afternoons
- Quick-dry fabrics79% average humidity
- Rain jacket and waterproof shoes5.4 in of rain on average
- Comfortable walking shoesmost places below are best reached on foot or with short walks
What to do in Seoul in September
With 5.4 in of rain, these picks lean toward food, drink and places with a roof, with outdoor options when the weather breaks.
Changdeokgung Secret Garden (Huwon)
Guided walks through a royal garden of ponds, pavilions and old trees behind Changdeokgung.
Why now Our curated notes say it's best autumn.
Bukhansan National Park
Granite peaks inside city limits; the Baegundae summit hike takes about 4 hours round trip.
Why now Our curated notes say it's best autumn morning.
National Museum of Korea
Free national collection spanning gold Silla crowns to Joseon ceramics.
Why now An indoor-leaning stop for a month with 5.4 in of rain.
N Seoul Tower
Tower atop Namsan with a cable car and city views stretching to the mountains.
Myeongdong Kyoja
Long-running spot for kalguksu knife-cut noodles and dumplings since 1966.
Why now A sit-down stop to wait out showers in a month with 5.4 in of rain.
Nearby in September
- Gyeongju in September~172 mi · highs 76°F, 6.2 in rain · similar daytime temperatures, wetter
- Busan in September~202 mi · highs 76°F, 7.4 in rain · similar daytime temperatures, wetter
NASA POWER 2001–2025 monthly averages on a ~50 km grid. Comfort scores weigh temperature, rain, humidity and cloud: see how we score each month. Check a forecast before you go.
Seoul in September: quick answers
Is September a good time to visit Seoul?
It's middling, scoring 73/100. The best months are May and October, at up to 94. Expect highs of 76°F (25°C) and 5.4 in (138 mm) of rain. September is inside the Apr – Jun, Sep – Nov window our Seoul, Gyeongju & Busan route recommends.
How hot is Seoul in September?
Average highs are 76°F (25°C) and average lows 62°F (17°C), making it the 4th-warmest month by daytime highs.
Does it rain a lot in Seoul in September?
Yes: about 5.4 in (138 mm) of rain falls across September on average, the 3rd-wettest month of the year. The annual total is about 48.9 in (1241 mm).
What should I pack for Seoul in September?
Bring light, breathable clothes (76°F afternoons), quick-dry fabrics (79% average humidity), rain jacket and waterproof shoes (5.4 in of rain on average) and comfortable walking shoes (most places below are best reached on foot or with short walks).
Routes in season in September
- Seoul, Gyeongju & Busan Apr – Jun, Sep – Nov
Planning Seoul in September?
Share this September plan with your group, poll everyone on dates and keep the packing list in one place.