Seoul weather by month & the best time to visit
South Korea · major coastal city · humid subtropical climate
The best time to visit Seoul is June — its sunniest month (Sunshine Score 72/100), with October and September close behind. Seoul averages about 2,037 hours of sunshine a year. Daytime highs around 21°C / 70°F and roughly 103 mm of rain in June.
When is the best time to visit Seoul?
For sunshine, the best time to visit Seoul is June, then October and September. The dullest month is January (0/100, 22 mm of rain). The full month-by-month picture is in the table below.
How sunny is Seoul?
Seoul gets a moderate 2,037 hours of sunshine a year. 72 Sunshine Score points separate June (72) from January (0), so the month you pick matters. It ranks #4 of 14 destinations in South Korea for annual sunshine, above the national median of 1,959 hours. Rain has a clear season: the wettest stretch, around August, carries about 59% of the annual 1,174 mm.
Sunshine Score by month
| Month | Score | Day high | Night low | Rain | UV | Sea |
|---|---|---|---|---|---|---|
| January | 0 | 1° / 34°F | -2° / 28°F | 22 mm | 2 | 2° / 36°F |
| February | 0 | 3° / 37°F | -1° / 30°F | 32 mm | 2 | 2° / 36°F |
| March | 0 | 6° / 43°F | 2° / 36°F | 36 mm | 3 | 5° / 41°F |
| April | 26 | 12° / 54°F | 7° / 45°F | 69 mm | 5 | 12° / 54°F |
| May | 56 | 17° / 63°F | 12° / 54°F | 86 mm | 6 | 17° / 63°F |
| June | 72 | 21° / 70°F | 18° / 64°F | 103 mm | 5 | 23° / 73°F |
| July | 63 | 25° / 77°F | 22° / 72°F | 323 mm | 5 | 26° / 79°F |
| August | 63 | 26° / 79°F | 23° / 73°F | 246 mm | 6 | 30° / 86°F |
| September | 67 | 24° / 75°F | 20° / 68°F | 129 mm | 5 | 28° / 82°F |
| October | 68 | 18° / 64°F | 14° / 57°F | 51 mm | 4 | 20° / 68°F |
| November | 20 | 11° / 52°F | 7° / 45°F | 51 mm | 2 | 15° / 59°F |
| December | 0 | 4° / 39°F | 0° / 32°F | 26 mm | 1 | 6° / 43°F |
Sea temperature in Seoul by month
The sea off Seoul is warmest in August at around 30°C / 86°F, and coolest in January at 2°C / 36°F. The water sits at a comfortable 21°C or warmer roughly 4 months a year. Month-by-month sea-surface temperatures are in the Sea column of the table above.
Nearest destinations
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Head-to-head
How Seoul compares month by month: Seoul vs Cheongju · Seoul vs Gunsan · Seoul vs Yangyang · all comparisons
Seoul: questions and answers
What kind of destination is Seoul?
Seoul is a major coastal city in South Korea with a humid subtropical climate — the sea reaches 30°C at its warmest and is swimmable (21°C+) about 4 months a year.
How many hours of sunshine does Seoul get a year?
Seoul gets about 2,037 hours of sunshine a year, at its best around June.
When is the best time to visit Seoul?
The sunniest time to visit Seoul is June, when the Sunshine Score peaks at 72/100 (with October and September close behind). Expect daytime highs around 21°C / 70°F.
What is the least sunny month in Seoul?
January is the least sunny month in Seoul, scoring 0/100 with about 22 mm of rain.
What is the sea temperature in Seoul?
The sea in Seoul ranges from about 2°C (January) to 30°C (August). Month-by-month sea temperatures are on this page.
How strong is the sun in Seoul?
The typical midday UV index in Seoul peaks around 6 (high) in May, easing to about 1 (low) in December. Month-by-month midday UV values are in the UV column of the table on this page.
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