Even within South Korea, Seoul's weather stands apart because of its population density and dense urban terrain. From the Han River running through the city and the mountains ringing it — Bukhansan, Gwanaksan, and more — to the urban heat-island effect created by tightly packed buildings and roads, here's a breakdown of Seoul's weather patterns, historical records, and seasonal tips.
The Han River cuts through the city, with mountains large and small — Bukhansan and Dobongsan to the north, Gwanaksan to the south — ringing Seoul. Its terrain mixes inland and coastal characteristics, so extreme heat waves and cold snaps tend to be somewhat milder than in inland basin regions. But with an extremely dense population, traffic, and buildings, the heat and pollution the city generates on its own have a bigger impact than in any other Korean city.
South of the Han River (Gangnam) has relatively wider flat ground and was developed later, giving heat somewhat more room to dissipate. The older Gangbuk city center, with its narrow alleys and older buildings, tends to hold higher nighttime temperatures in summer.
On autumn and winter mornings, moisture from the Han River cools and often produces thick fog along the riverside roads. Take extra care with visibility early in the morning on roads like Olympic-daero and Gangbyeon-bukro.
Asphalt and concrete absorb heat during the day and release it slowly at night, so downtown temperatures don't drop as much overnight as they do in the outskirts. As a result, Seoul sees more tropical nights than other regions, and heat waves tend to feel more intense.
Spring often brings yellow dust and fine dust blowing in from China and Mongolia, compounded by Seoul's own dense traffic and heating emissions, so air quality swings widely. In summer, the heat-island effect is pushing tropical-night counts higher. In winter, watch for Han River fog along with localized gusts funneled between buildings ("building wind"). For general season-by-season tips, see the seasonal outdoor guide.
Based on official KMA observations at the Seoul Weather Station (Songwol-dong, Jongno-gu).
| Record | Value | Date |
|---|---|---|
| Record high | 39.6°C | 2018-08-01 |
| Record low | -23.1°C | 1927-12-31 |
| Heaviest daily snowfall | 25.8cm | 2010-01-04 |
On summer nights when the heat-island effect keeps temperatures up, cooling indoor spaces earlier in the day and airing rooms out briefly before bed helps. On days with heavy spring fine dust, riverside parks along the Han tend to be a better bet than roadside streets downtown. For general threshold-by-threshold guidance on UV, feels-like temperature, and fine dust, see what to do.
Because conditions can vary a lot between Seoul's districts and neighborhoods, searching for and adding your specific neighborhood in sanCheck gives you a more accurate weather and outdoor-activity score. Save the places you check often — home, work — and tap between chips to compare.