Climate averages 1991–2020
Seosan weather
in January.
A cold, fairly dry month: the coolest and the driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
January is a cold month in Seosan: daytime highs average 2.5°C and nights cool to about -2.8°C. By daytime temperature it is the coolest month of the year.
Expect about 22 mm of rain on roughly 5 days, which makes January a fairly dry month (the driest month of the year). Daylight, from sunrise to sunset, lasts about 9 h 57 min on an average January day.
The nearest other city in this atlas is Hongseong (28 km away). In January its highs average 2.9°C, about as warm as Seosan, with 22 mm of rain.
Among the 79 cities listed in South Korea, Seosan ranks joint 48th of 79 for the warmest January highs and joint 27th of 79 for the driest January (rainfall, lowest first). The mean January high of those 79 cities is 3.6°C; Seosan is 1.1°C cooler than that mean.
From January to February, average highs rise by 1.9°C to 4.4°C, and monthly rainfall rises from 22 mm to 28 mm.
The annual picture
January 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
Seosan climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January, selected | 2.5°C-2.8°C | -2.8°C | 22 | 4.8 | 9.910 h |
| February | 4.4°C-1.9°C | -1.9°C | 28 | 4.3 | 10.811 h |
| March | 9.0°C1.7°C | 1.7°C | 41 | 5.6 | 11.912 h |
| April | 15.1°C6.8°C | 6.8°C | 69 | 6.8 | 13.113 h |
| May | 20.3°C12.2°C | 12.2°C | 79 | 7.0 | 14.114 h |
| June | 24.6°C17.3°C | 17.3°C | 116 | 7.7 | 14.615 h |
| July | 27.0°C21.9°C | 21.9°C | 245 | 14.8 | 14.414 h |
| August | 27.9°C22.9°C | 22.9°C | 225 | 13.7 | 13.614 h |
| September | 24.2°C18.4°C | 18.4°C | 133 | 7.5 | 12.512 h |
| October | 18.6°C12.3°C | 12.3°C | 55 | 5.3 | 11.311 h |
| November | 11.7°C5.7°C | 5.7°C | 49 | 7.2 | 10.210 h |
| December | 5.0°C-0.5°C | -0.5°C | 26 | 6.1 | 9.710 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
January in nearby cities
- Hongseong in JanuarySouth Korea · 28 kmHigh 2.9°C · Low -3.9°C · 22 mm rain
- Asan in JanuarySouth Korea · 49 kmHigh 2.6°C · Low -4.8°C · 21 mm rain
- Boryeong in JanuarySouth Korea · 50 kmHigh 3.4°C · Low -2.3°C · 25 mm rain
- Hwaseong-si in JanuarySouth Korea · 57 kmHigh 1.8°C · Low -3.9°C · 22 mm precipitation
- Pyeongtaek in JanuarySouth Korea · 61 kmHigh 2.3°C · Low -5.2°C · 20 mm rain
- Cheonan in JanuarySouth Korea · 62 kmHigh 2.7°C · Low -4.7°C · 22 mm rain
- Ansan-si in JanuarySouth Korea · 69 kmHigh 1.9°C · Low -4.9°C · 22 mm precipitation
- Osan in JanuarySouth Korea · 69 kmHigh 2.2°C · Low -5.5°C · 20 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 Seosan) is explained once on the Seosan year overview and on the Sources, method and limits page.