Climate Chart of Jeju, South Korea

Climate overview

Temperature

The monthly mean temperature is lowest in January, at 6.1 °C, and reaches its highest point in August, at 27.4 °C. These are averages for whole months, not daytime highs, so visitors should not read them as a forecast of afternoon conditions or the full range of temperatures they may encounter. Across the calendar-month means, the unweighted mean is 16.3 °C. It provides a compact overview of the temperature data, but is not a day-weighted annual average and does not indicate how often individual days are warmer or cooler.

Rain

Mean daily rainfall is lowest in January, at 2.00 mm/day, making it a conditional option for visitors prioritising lower average rainfall. The highest monthly mean is in September, at 9.37 mm/day; visitors planning around that average can pack rain protection and keep plans flexible. Neither figure gives the frequency of rainy days or guarantees dry or wet conditions on a particular visit. The unweighted mean across monthly mean daily rainfall values is 4.59 mm/day. These are daily averages rather than monthly totals, so they should not be interpreted as the amount expected on every day.

Snow

The highest monthly mean daily snowfall is recorded in January, at 4.97 mm/day. The unweighted mean across the monthly snowfall averages is 1.12 mm/day per day. These amounts describe averages, not the number of snowy days, snow depth, snow cover or skiing conditions.

Sunshine

Mean daily sunshine duration is highest in August, at 9.74 hours/day, and lowest in January, at 5.25 hours/day. Visitors using sunshine averages to plan outdoor sightseeing may find these contrasts useful, while allowing for day-to-day weather; sunshine duration is not the same as day length. The unweighted mean of the monthly sunshine averages is 7.65 hours/day per day. It summarises the monthly data without promising that any particular day will receive that duration of sunshine.