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Seoul gets more rain in September than in October and November combined. Afternoons that month still average 26°C, close to June’s 27.6°C. Most of what visitors mean by a Korean autumn, the cool air and the turning leaves, arrives in October.
Seoul, September to November
Seoul, on the Korea Meteorological Administration’s 1991 to 2020 normals.
| Average high | Average low | Rainfall | Wet days | |
|---|---|---|---|---|
| September | 26.2°C / 79°F | 17.7°C / 64°F | 141.5mm | 9.1 |
| October | 20.2°C / 68°F | 10.6°C / 51°F | 52.2mm | 6.1 |
| November | 11.9°C / 53°F | 3.5°C / 38°F | 51.1mm | 8.8 |
Rain falls on only about six October days, the lowest count of the three. Afternoons reach twenty degrees and nights to about eleven, so pack layers you can take off.
November is coat weather. Afternoons average 11.9°C. Its rainfall is almost identical to October’s but spread over more days.
From September to November the average high drops by fourteen degrees.
September’s leftover summer
Typhoons are part of this. On the weather service’s normals, an average of 0.8 typhoons affect the Korean peninsula in September, against 0.1 in October. If cooler, drier weather is why you chose autumn, October is the month that delivers it.
Foliage in 2026
A national foliage forecast comes out each year between late September and early October, from the Korea Forest Service. The 2026 map, announced on 22 September, puts the nationwide peak in late October, a little under a day behind the recent five-year average. Colour starts in the northern mountains of Gangwon in early October.
| Forecast peak | |
|---|---|
| Seoraksan | 20 October |
| Songnisan | 28 October |
| Naejangsan | 4 November |
| Hallasan | 6 November |
From the first of those peaks to the last is seventeen days, moving north to south. By tree species, maples and oaks peak on 31 October and ginkgos on 30 October.
Seoul does not appear in the mountain list. If your trip is in November and the leaves are the point, the latest forecasts are the southern ones.
Sunset
| Sunset in Seoul | |
|---|---|
| 1 October | about 6.15pm |
| 15 October | about 5.55pm |
| 31 October | about 5.35pm |
| 15 November | about 5.20pm |
| 30 November | about 5.15pm |
October alone loses forty minutes of evening. By the end of November the sun is down an hour earlier than at the start of October. Outdoor sightseeing works best before lunch.
Palace nights end early
Gyeongbokgung’s autumn night viewing opened on 2 September and closed on 2 October, the palace announced, with no sessions on Mondays or Tuesdays. There is no night entry for the rest of the season.
Daytime tours continue. Special viewing of the Gyeonghoeru and Hyangwonjeong pavilions, rooms at Gyeongbokgung that are otherwise closed, runs at 10am and 2pm on Wednesdays and Fridays until 30 October.
Both keep fixed dates instead of opening daily, and the booking page on the royal palaces site is where they are announced.