Climate averages 1991–2020
Jeju City weather
in September.
A warm, wet month: the 3rd warmest and the 9th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Jeju City: daytime highs average 25.3°C and nights cool to about 22.3°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 165 mm of rain on roughly 11 days, which makes September a wet month (the 9th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 25 min on an average September day.
The nearest other city in this atlas is Seogwipo (29 km away). In September its highs average 26.0°C, 0.7°C warmer than Jeju City, with 183 mm of rain.
Among the 79 cities listed in South Korea, Jeju City ranks joint 15th of 79 for the warmest September highs and 67th of 79 for the driest September (rainfall, lowest first). The mean September high of those 79 cities is 24.8°C; Jeju City is 0.6°C warmer than that mean.
From September to October, average highs fall by 4.6°C to 20.7°C, and monthly rainfall falls from 165 mm to 79 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Jeju City climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 8.0°C4.7°C | 4.7°C | 73 | 11.7 | 10.210 h |
| February | 9.1°C5.0°C | 5.0°C | 65 | 9.4 | 11.011 h |
| March | 12.2°C7.5°C | 7.5°C | 94 | 10.3 | 12.012 h |
| April | 16.4°C11.4°C | 11.4°C | 102 | 8.9 | 13.013 h |
| May | 20.1°C15.5°C | 15.5°C | 109 | 8.8 | 13.914 h |
| June | 23.5°C19.7°C | 19.7°C | 189 | 11.5 | 14.314 h |
| July | 27.6°C24.3°C | 24.3°C | 184 | 12.1 | 14.114 h |
| August | 28.7°C25.7°C | 25.7°C | 168 | 13.7 | 13.413 h |
| September, selected | 25.3°C22.3°C | 22.3°C | 165 | 11.1 | 12.412 h |
| October | 20.7°C17.4°C | 17.4°C | 79 | 6.7 | 11.411 h |
| November | 15.8°C11.9°C | 11.9°C | 70 | 8.8 | 10.510 h |
| December | 10.5°C6.8°C | 6.8°C | 68 | 11.0 | 10.010 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Seogwipo in SeptemberSouth Korea · 29 kmHigh 26.0°C · Low 21.8°C · 183 mm rain
- Mokpo in SeptemberSouth Korea · 145 kmHigh 24.5°C · Low 19.0°C · 149 mm rain
- Muan in SeptemberSouth Korea · 165 kmHigh 25.4°C · Low 18.4°C · 147 mm rain
- Yeosu in SeptemberSouth Korea · 174 kmHigh 24.5°C · Low 20.1°C · 160 mm rain
- Masan in SeptemberSouth Korea · 182 kmHigh 25.8°C · Low 17.5°C · 145 mm rain
- Suncheon in SeptemberSouth Korea · 183 kmHigh 25.9°C · Low 18.4°C · 160 mm rain
- Gwangju in SeptemberSouth Korea · 186 kmHigh 25.7°C · Low 17.2°C · 138 mm rain
- Kwangyang in SeptemberSouth Korea · 190 kmHigh 25.7°C · Low 18.8°C · 160 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Jeju City) is explained once on the Jeju City year overview and on the Sources, method and limits page.