Seoul Weather in September: What to Expect
In September, Seoul averages highs of 25.3°C and lows of 17.1°C, with about 9 rainy days (~133 mm). Verdict: Good — comfortable — manageable 25.3°C days. That makes it the 2nd hottest of South Korea's 6 main cities this month.
Seoul vs other South Korea cities in September
South Korea is not one climate. In September, Jeju runs to 25.6°C while Sokcho sits at 23.3°C — a 2°C spread. Here is where Seoul falls:
What to pack for Seoul in September
With highs near 25.3°C and lows around 17.1°C, pack light summer clothing plus a thin layer for evenings, a compact umbrella or rain shell.
What to do in Seoul in September
September's weather suits sightseeing through the day. Top sights:
Public holidays in South Korea, September
- 2026-09-24 — Chuseok
- 2026-09-25 — Chuseok
- 2026-09-26 — Chuseok
- 2027-09-14 — Chuseok
- 2027-09-15 — Chuseok
- 2027-09-16 — Chuseok
Seoul in September — FAQs
What is the weather like in Seoul in September?
In September, Seoul averages daytime highs of 25.3°C and overnight lows around 17.1°C, with roughly 9 rainy days and about 133 mm of rain across the month. Good — comfortable — manageable 25.3°C days.
Is September a good time to visit Seoul?
Good — comfortable. September is comfortable enough for full-day sightseeing in Seoul. Among South Korea's cities, Seoul is the 2nd hottest this month.
What should I pack for Seoul in September?
For September (17.1–25.3°C), pack light summer clothing plus a thin layer for evenings, a compact umbrella or rain shell.
What is there to do in Seoul in September?
Seoul's main sights include Changdeokgung, Gyeongbokgung, Hwaseong Fortress, Namsan Seoul Tower. The weather suits visiting these comfortably through the day.
Are there public holidays in South Korea in September?
Yes — Chuseok (2026-09-24), Chuseok (2026-09-25), Chuseok (2026-09-26), Chuseok (2027-09-14), Chuseok (2027-09-15), Chuseok (2027-09-16). Sites can be busier or closed around these dates.
Seoul weather by month: