Jeju Island, South Korea

Set in an ocean-tempered climate, Jeju Island (South Korea) is best understood through its weather data: our 2015–2024 climate record puts its peak at an 82/100 sun score in May, exactly the kind of reliability you want for a nature-first trip.

Across a typical year, afternoon temperatures swing between 7°C (January) and 29°C (August). Rain is most likely in September, when about 60% of days see meaningful rainfall, and least likely in April (31%). If 24°C is your bar for proper warmth, count on June–September.

The seasonal arc is clear in the data: summer averages 28°C against winter's 9°C, while rain-day odds move from 43% in winter and 34% in spring to 54% in summer and 45% through autumn. Summer wins on the numbers and winter loses them; everything in between is a trade-off between warmth and crowds. If your dates are flexible, September buys you 26°C warmth at the quiet end of the season.

Best months to visit Jeju Island

The best month on record is May — an 82/100 sun score, built on 65% cloud cover and 35% rain-day odds — followed by August and October. In practice you have flexibility — May–October all stay above a 70 sun score. At the other end, January scores just 45, the weakest month of the year.

For context: in May, Jeju Island is drier than 26% of the ocean destinations we track.

Month-by-month breakdown for Jeju Island → · More destinations for May →

Right now the 16-day outlook shows 3 mostly-clear days (under 40% cloud) and 2 with real rain risk, with temperatures between 6°C and 21°C — which is how Jeju Island earns its current 64/100 sun score.