Seoul weather in September
“Mild and bright — an underrated time to visit.”
Roughly 9 rainy days across the month, on average.
September in Seoul brings pleasantly warm days and cool evenings. Expect average highs of 25.3°C (77°F) and lows of 17.1°C (63°F), making it comfortable for walking and sightseeing. The month sees about 127mm of rainfall spread across roughly 9 rainy days, so occasional showers are likely. You'll enjoy around 8.6 hours of sunshine daily, offering good conditions for outdoor exploration despite the moisture in the air.
This is prime season for Seoul's cultural calendar. September hosts the Chuseok harvest festival preparations, traditional performances at the National Theater, and various art exhibitions. The summer crowds have thinned, but the city remains lively with locals enjoying the transition to autumn. Parks and temples are particularly atmospheric as early autumn colors begin appearing.
For travelers planning a 2026 visit, September strikes an excellent balance. The weather is milder than summer's heat and humidity, yet warmer than October's crisp mornings. Pack layers and a compact rain jacket to handle the occasional downpours. It's an ideal month for first-time visitors who want pleasant temperatures without peak-season prices or crowds.
The city is split by the Han River and the neighborhoods have deep rivalries — Gangnam is nouveau-money, Gangbuk (Jongno, Ikseon-dong) is old-money and old-Seoul. Naver Maps works, Google Maps doesn't (Korean law blocks foreign mapping). Order at pojangmacha street tents late night in Jongno for sundae blood sausage and soju. The escalator etiquette is stand right, walk left, but on Seoul subway it's stand both sides — a Busan person will get annoyed.
What to pack for Seoul in September
Layer your clothing to adapt to Seoul's September conditions. Mornings and evenings are noticeably cooler, while midday warmth requires breathable fabrics. A lightweight rain jacket is essential given the 9 rainy days typical for this month. Comfortable walking shoes are crucial for exploring neighborhoods and temples.
- Light rain jacket or windbreaker
- Linen shirts or cotton t-shirts
- Lightweight cardigan or sweater
- Comfortable walking sneakers
- Compact umbrella
What to pack for Seoul in September
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Where to stay in Seoul
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Compare hotels on Booking.com→Estimated September trip to Seoul
Shoulder-season pricing — a balance of price and conditions. Rule-based estimates from a couple based in London — actual prices vary.
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Delayed flight to Seoul?
September sees 127mm of rain here — delays happen. Check if you're eligible for compensation. EU regulations cover flights departing from or arriving in the EU/UK.
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Things worth doing
Visit Bukchon Hanok Village and Gyeongbokgung Palace, hike Namsan Tower trail, explore street food markets in Myeongdong, catch traditional performances at the National Theater.
September vs. the rest of the year
How this month compares in Seoul. Tap any month to read more.
highlighted months are among the best time to visit.
Best time to visit Seoul
While September has its own character in Seoul, the data-backed best months to visit Seoul are April, October. These months combine the most favourable temperatures, rainfall, and sunshine across an 11-year climate record (2015–2025).
See the full best-time-to-visit guide for SeoulOther places with a similar climate right now
Seoul in September — FAQ
Q01Is September a good time to visit Seoul?
Is September a good time to visit Seoul?
It is a fair time to visit — expect variable conditions and plan flexibility. In September, Seoul averages a high of 25°C (78°F) and a low of 17°C (63°F), with 127mm of rainfall across roughly 9 rainy days. Mid-April cherry blossoms line the Yeouido Yunjungno road and the Han River picnic season officially opens with chimaek (chicken and beer) delivery from tents.
Q02What is the average temperature in Seoul in September?
What is the average temperature in Seoul in September?
The average high temperature in Seoul during September is 25°C (78°F), with an average low of 17°C (63°F). These figures are averaged from 11 complete years of daily records (2015–2025, Open-Meteo Archive).
Q03How many rainy days does Seoul have in September?
How many rainy days does Seoul have in September?
Seoul averages approximately 9 rainy days in September, with a total monthly rainfall of about 127mm. This is based on daily precipitation records where days with 1mm or more of rain are counted as rainy days. Late June through July jangma monsoon dumps 400mm; the Han rises past cycling paths and Gangnam intersections flood, stranding buses for hours.
Q04What should I pack for Seoul in September?
What should I pack for Seoul in September?
For Seoul in September, pack layered clothing for changing temperatures, a compact umbrella or waterproof jacket, sunscreen and sunglasses, comfortable walking shoes. These recommendations are based on 11 complete years of weather averages for this specific month. A folding fan (buchae) — locals of all ages carry one in summer and consider hand-fanning strangers a small kindness on packed subways.
Q05How crowded is Seoul in September?
How crowded is Seoul in September?
Tourist crowds in Seoul during September are typically moderate — shoulder season, a sweet spot between crowds and weather. Consider this when planning accommodation — prices track crowd levels closely. The city is split by the Han River and the neighborhoods have deep rivalries — Gangnam is nouveau-money, Gangbuk (Jongno, Ikseon-dong) is old-money and old-Seoul. Naver Maps works, Google Maps doesn't (Korean law blocks foreign mapping). Order at pojangmacha street tents late night in Jongno for sundae blood sausage and soju. The escalator etiquette is stand right, walk left, but on Seoul subway it's stand both sides — a Busan person will get annoyed.