Korea Weather & UV Index

Why the local forecast beats your default weather app

International weather apps model Korea from a distance. This page uses the Korea Meteorological Administration, the national agency Korean broadcasters, schools and workplaces act on, so a warning reaches you from the source rather than through a chain of guesses.

Korea is compact but not uniform. The Taebaek mountains split the peninsula's weather in two — a grey, wet morning in Seoul can be a bright one in Gangneung, and Jeju sits in its own milder, windier world. Pick the city you will actually be standing in, not the nearest big name on the list.

How to read the numbers

The same reading does not mean the same day here, because what makes a temperature bearable changes with the season.

• Check hours, not days. Summer rain arrives in bands, so a day marked as rainy is often two or three wet hours with sun on either side — reason to move a museum into the middle of the day rather than cancel.
• In summer, watch the humidity. The air temperature undersells how a Korean August feels; humidity is what makes a thirty-degree day punishing.
• In winter, watch the wind. A dry, still cold day is manageable; the same temperature with a sharp wind off the Han River is not.
• In spring and autumn, watch the gap between the high and the low. The air is dry and the swing from afternoon to evening can need two different layers in one day.
• Everything is metric. Temperature in Celsius, rainfall in millimetres, wind in metres per second.

The UV number most visitors ignore

UV peaks around midday and is strongest from late spring through summer. An overcast sky still lets a great deal of it through — cloud is not sunscreen, and a cool day can carry a high reading, because UV follows the angle of the sun rather than the temperature.

It matters here because so much Korean sightseeing happens in the open — palace courtyards, temple stairways, the coastal paths in Busan. Sunscreen is cheap in any convenience store, and using a folding umbrella as a parasol is normal.

What each season really does

• Spring — mild and crowded. Cherry blossom usually opens in the far south in late March and reaches Seoul in early April, shifting by a week or more from year to year. It is also yellow dust season, so pair this page with the air quality tool.
• Summer — hot, wet and heavy, with the muggiest stretch usually arriving once the rainy season lifts. Typhoons can brush the peninsula in late summer and early autumn.
• Autumn — the clearest and most settled weather of the year, which is why every hiking trail is busy in October.
• Winter — cold, dry and often bright inland, with the heaviest snow falling on the east coast and in the mountains rather than on Seoul.

A forecast is a prediction. When the Korea Meteorological Administration issues a warning for heat, cold, snow, wind or heavy rain, that takes priority over anything here, and the UV guidance above is general information, not medical advice.

Frequently asked questions

When is the best weather for visiting Korea?
Autumn, roughly late September through November, is the most comfortable stretch of the year — mild, settled and far less humid than summer. Driest is a different question: measured by rainfall the driest season is winter, simply too cold for easy sightseeing. Spring is a close second if you accept the crowds and the occasional dusty day.

Do I need to pack an umbrella for Korea?
There is little point packing a large one — cheap folding umbrellas are sold in every convenience store the moment it starts raining. Expect plastic sleeves or umbrella stands at building entrances, since dripping on indoor floors is considered bad manners.

How cold does a Korean winter actually get?
Seoul drops well below freezing on January nights and the wind makes it feel harsher still, while Busan and Jeju stay noticeably milder. Layers plus a windproof outer shell cope with it far better than one very thick coat.

When is the summer rainy season?
The rain front known as jangma normally reaches Jeju first and works north over the peninsula, with the wettest weeks falling somewhere between late June and late July. Its start and end shift by a week or two each year, so treat them as a window rather than a date; a large share of the year's rainfall arrives in July and August.