Seoul City Guide
Seoul Weather Month by Month
Seoul weather by month is a story about two extremes and two short perfect seasons: a dry cold winter, a monsoon that drops most of the year's rain in July and August, and the spring and autumn in between. Figures on this page are the Korea Meteorological Administration's 1991–2020 normals, checked in Q3 2026. The trip they shape is on the Seoul city guide homepage.
Quick answer July drops 414 mm, January 17 — the two months to book and the two to avoid
Seoul has a continental climate with a monsoon on top. Winter is cold and very dry — January averages −2 °C and 17 mm of rain. Summer is hot, humid and wet — August averages 26 °C and July drops 414 mm. Between them, May and October are close to ideal: high teens to low twenties, low rainfall, clear light. Those two months are also when everything is booked.
Key takeaways
- Avoid July if you can. It rains more in that one month than in the whole of winter, spring and autumn combined.
- November is the underrated month: cold, clear, dry and empty, with the last of the foliage.
- August heat is not just uncomfortable — the palace guard ceremonies are cancelled during heat advisories.
Seoul Month by Month
Mean daily maximum temperature by month in Celsius, with the Fahrenheit reading underneath, from the Korea Meteorological Administration's 1991–2020 climate normals for Seoul.
The bars are the mean daily maximum; the daily mean is lower and appears in the table below. August is the hottest month at 30.0°C average high, July the wettest at 414 mm, and January the driest at 16.8 mm. The season bands come from the 2026 palace and museum calendars and from our own reading of the visitor season, which is labelled as such.
Every Month, With the Numbers
Daily mean and mean daily maximum temperature, and monthly rainfall, from the Korea Meteorological Administration 1991–2020 normals for Seoul, checked in Q3 2026. Fahrenheit conversions are rounded.
| Month | Mean | Daily max | Rain | What it means |
|---|---|---|---|---|
| January | -2.0 °C | 2.1 °C | 16.8 mm | Cold and dry, clearest air of the year |
| February | 0.7 °C | 5.1 °C | 28.2 mm | Cold; Seollal closes museums for the day |
| March | 6.1 °C | 11.0 °C | 36.9 mm | Warming, still bare; palace night viewing seasons begin |
| April | 12.6 °C | 17.9 °C | 72.9 mm | Blossom, and the Huwon garden sells out |
| May | 18.2 °C | 23.6 °C | 103.6 mm | The best month; lantern season at Jogyesa |
| June | 22.7 °C | 27.6 °C | 129.5 mm | Humid from mid-month; monsoon starts |
| July | 25.3 °C | 29.0 °C | 414.4 mm | Wettest month by a wide margin — 414 mm |
| August | 26.1 °C | 30.0 °C | 348.2 mm | Hottest; guard ceremonies cancelled in heat advisories |
| September | 21.7 °C | 26.2 °C | 141.5 mm | Humidity drops; Chuseok closes the museums for a day |
| October | 15.0 °C | 20.2 °C | 52.2 mm | The best month; everything books out |
| November | 7.5 °C | 11.9 °C | 51.1 mm | Cold, clear, quiet — the underrated one |
| December | 0.2 °C | 4.2 °C | 22.6 mm | Cold and dry; the towers are at their sharpest |
Total annual rainfall is about 1,418 mm, and July and August account for more than half of it. The dry season is genuinely dry: January's 17 mm is less than a wet afternoon in London.
The Monsoon, and What It Actually Does
Jangma, the East Asian monsoon front, usually arrives in Seoul in late June and sits over the peninsula into late July. It does not rain continuously — that is the common misunderstanding — but it delivers heavy, concentrated rainfall, and 414 mm in July against 17 mm in January tells you the shape of it.
What that means in practice: sudden downpours rather than drizzle, flash flooding in low-lying streets, and hiking trails closed after heavy rain. The Cheonggyecheon walkway closes during storm warnings, and Bukhansan sections shut after prolonged rain.
August adds typhoons. Two or three reach the peninsula in a typical season, mostly in August and September, and they close outdoor attractions for a day at a time.
The city copes well — drainage is good, the metro is unaffected, and everything indoors carries on. But an August itinerary needs indoor fallbacks: the free national museums, Lotte World's covered park, the malls, and a jjimjilbang.
The Heat and the Cold, Honestly
August in Seoul averages 26 °C, which sounds mild and is not. Humidity carries the discomfort, the city holds heat in its concrete, and heat advisories are common enough that outdoor programmes are suspended — Gyeongbokgung's guard ceremonies stop during them, and the special palace viewings pause for the whole of June to August.
January averages −2 °C and regularly drops well below that, with wind coming down from the north. It is a dry cold and it is manageable with proper clothing, but the mountain trails ice and the city wall sections become genuinely hazardous without crampons.
The compensation is air quality. Winter days in Seoul are frequently the clearest of the year, which is why the observatories are worth their price in January and often not in April, when fine dust can flatten the view to a grey wall.
Spring dust is the season nobody warns you about: fine particulate levels rise in March and April, and on bad days the city issues advisories. Check before paying for a view.
What to Bring, by Season
Winter, December to February. A proper coat, gloves and something for your ears. Indoor heating is aggressive, so layers you can remove. Shoes with grip if you plan to walk the city wall or Bukhansan.
Spring, March to May. Layers and a light jacket; March is colder than the number suggests and May can be warm by afternoon. A mask on high fine-dust days, which are announced on every weather app.
Summer, June to August. As little as possible, plus a compact umbrella that lives in your bag from mid-June. Convenience stores sell them everywhere for a few thousand won when you inevitably fail to carry one.
Autumn, September to November. The easy season: a jacket in the evening, and by November a proper coat. This is when Seoul is at its best and when you will need to have booked ahead.
What to Read Next
Three pages that use these numbers.
Best time to visit
Crowds, prices and events on top of the weather: when to visit Seoul.
- May and October peak
- November underrated
- August cheapest
Cherry blossom
When the blossom actually arrives and where to see it: Seoul cherry blossom.
- Dates shift each year
- Yeouido is the crowd
- One week of it
Seoul in winter
The cold, clear, cheap version of the city: Seoul in winter.
- Clearest air
- Empty palaces
- Crampons for the trails
Weather Questions
What is the best month to visit Seoul?
May or October: high teens to low twenties, low rainfall and clear light. Both are also the busiest and most expensive — the best-time page weighs that trade.
When is the rainy season in Seoul?
Late June into late July, with July averaging 414 mm — nearly a third of the annual total. August adds typhoon risk. It comes as heavy downpours rather than continuous drizzle.
How cold does Seoul get in winter?
January averages −2 °C as a daily mean, with a mean daily maximum of 2 °C, and regularly drops well below that. It is a dry cold with clear skies and very little precipitation — about 17 mm in the month.
Is August a bad time to visit Seoul?
It is the hardest month: 26 °C with high humidity, 348 mm of rain, typhoon risk and heat advisories that suspend outdoor programmes. It is also the cheapest and least crowded.
What is fine dust season in Seoul?
March and April, when particulate levels rise and the city issues advisories. It affects visibility from the observatories more than it affects daily comfort.
When is the autumn foliage in Seoul?
Late October into early November in the city, slightly earlier on Bukhansan. It is the most popular fortnight of the Korean year for domestic travel.
Reviewed Q3 2026 (July–September 2026); next review Q4 2026. Prices, hours and terms are set by the venue or operator and confirmed at checkout.
We may earn a commission if you book through one of our links, at no extra cost to you. Full affiliate disclosure