September is one of Seoul’s finest months to visit. The summer heat and humidity break in the first week of September, leaving warm, dry days ideal for outdoor sightseeing.
The first hints of autumn foliage appear by late September. Chuseok (the Korean harvest festival) falls in September or October, and while it causes transport disruption, it also gives the city a distinctive festive character. Here is the complete guide to Seoul in September.
Quick Answer: Seoul in September Warm and dry (highs of 22 to 28 degrees, dropping to 15 to 18 by late September). One of Seoul’s best months for outdoor sightseeing. Watch for Chuseok dates (varies yearly) as transport books up and some businesses close. See the Korea in September for the national Korea September guide.
Seoul Weather in September
Early September (1 to 10)
Highs of 26 to 30 degrees. Lows of 20 to 23 degrees. Still warm with some humidity, similar to late August. Occasional afternoon showers. The summer heat is fading but not yet fully gone.
Mid-September (11 to 20)
Highs of 23 to 27 degrees. Lows of 15 to 18 degrees. The optimal Seoul weather window. Clear skies, low humidity, warm enough for light clothes during the day, and comfortable evenings. Outdoor activities and palace visits are at their best.
Late September (21 to 30)
Highs of 20 to 24 degrees. Lows of 12 to 15 degrees. A light jacket is needed in the evenings. The first autumn colours are beginning to appear in the mountains (Bukhansan, Seoraksan). This is when autumn begins in Seoul.
See the Japan packing guide for what to pack in the shoulder season.
Chuseok in September
Chuseok (Korean Thanksgiving, Hangawi) falls on the 15th day of the 8th lunar month, which places it in September or October depending on the year. In 2026, check the exact dates before booking. Key things to know:
- The 3-day Chuseok holiday (the day before, the day of, and the day after) sees mass travel across Korea as families return to their hometowns. KTX and bus tickets sell out weeks in advance for travel around the holiday dates.
- Many smaller restaurants and shops in Seoul close for the Chuseok holiday. Department stores and tourist-oriented businesses generally remain open.
- The palaces host special Chuseok performances and traditional activities, with free entry to Gyeongbokgung Palace and Changdeokgung Palace, and guides on Chuseok day itself.
- Arriving in Seoul for Chuseok rather than departing can be strategic: transport TO Seoul is manageable, while transport from Seoul to the provinces is packed.
What to Do in Seoul in September
Outdoor Sightseeing
September’s weather is ideal for palace visits, Bukhansan hiking (see the Korea hiking guide), the Cheonggyecheon Stream walk, and Han River parks (Yeouido Hangang Park). The reduced humidity makes outdoor activities significantly more comfortable than in August.
Seoraksan National Park
Late September is the beginning of Seoraksan’s autumn foliage season, usually starting with the upper peaks and descending through October. See the Seoraksan guide and the Sokcho guide for the Seoraksan base town.
Jeonju
September is an excellent time for a day trip or an overnight stay in Jeonju, the hanok village and food city, 2 hours from Seoul by KTX. The September weather makes the outdoor hanok village walks particularly pleasant.
Seoul Food in September
Chuseok season brings seasonal foods: songpyeon (half-moon rice cakes filled with sesame, chestnut, or red bean), seasonal namul (vegetable side dishes), and traditional Korean sweets. Many restaurants and market stalls feature Chuseok-themed menus in the weeks leading up to the festival. See the Korean food guide and the Seoul food guide.
Crowds in Seoul in September
September is shoulder season: noticeably less crowded than the July-August peak and the October autumn foliage rush. Mid-September is particularly manageable at major sites. The exception is Chuseok week, when the palaces and tourist areas in Seoul are busy with domestic visitors. See the Korea first-time tips for the full year-round crowd guide.
September Events in Seoul
- Seoul International Marathon: Usually held in mid-September. The marathon route passes major Seoul landmarks.
- Seoul Fringe Festival: Independent performing arts festival held in late August to early September in Hongdae (see Hongdae guide).
- Chuseok special events: Palace performances, traditional games at Namsangol Hanok Village, and cultural programmes at Gyeongbokgung Palace.
Nearby Guides
- Korea in September
- Seoul in October
- Seoul in November
- autumn in Korea
- Seoul travel guide
- Seoul in 3 days
- Best places to visit in Korea
FAQ
Is September a good time to visit Seoul?
Yes, strongly. Mid-September (10 to 25 September) is arguably Seoul’s single best weather window: warm, dry, low-humidity, and before the October autumn-colour crowds arrive. See the broader “best time to visit Korea” guide for the full seasonal comparison.
What is Chuseok, and how does it affect travel to Seoul?
Chuseok is Korea’s major harvest festival, equivalent in cultural importance to Christmas in Western countries. Families across Korea return to their hometowns for 3 days. This means KTX and express buses fill up weeks in advance around the holiday dates. Book transport well in advance if travelling during Chuseok, or plan your main travel before or after the holiday window.
Does it rain a lot in Seoul in September?
Early September can have carryover rain from the summer monsoon season (the monsoon ends in late July, but late-summer showers continue into early September). From mid-September onward, Seoul is typically dry and clear. Please check the forecasts for the specific week of your visit.
