Sejong climate — normals and trends
Sejong (South Korea) has a hot-summer humid continental, dry winter climate (Dwa) under the Köppen-Geiger classification. Its mean annual temperature is 12.5 °C and it receives 1,166 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is August (25.8 °C on average) and the coldest is January (-1.8 °C). Rainfall peaks in July.
Sejong averages 103 frost days, 38 hot days (≥ 30 °C) and 99 rainy days per year.
Sejong has warmed by +2.1 °C between 1940 and 2025, or +0.25 °C per decade. This trend is statistically significant.
The number of frost days there went from about 115 to 91 per year over the period.
The hottest day of the period reached 40.4 °C (on 15 August 2018) and the coldest -21.7 °C (on 25 January 1941).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
SejongSejong-si
- coords
- 36.59°, 127.29°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
12.5°C
Average daily high
17.5°C
Average daily low
8.1°C
Annual rainfall
1,166mm
Sunshine / day
8.8h
Mean relative humidity
70%
Average peak wind
14.3km/h
Seasonal range
27.6°C
Frost days (< 0 °C)
103 d/yr
Hot days (≥ 30 °C)
38 d/yr
Rainy days (≥ 1 mm)
99 d/yr
Annual snowfall
17.4 cm
Average feels-like high
16.5 °C
Average feels-like low
6.7 °C
Average peak gust
33.5 km/h
Tropical nights (≥ 20 °C)
61 d/yr
Solar radiation
14.9 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.1 °C
since 1940
+0.3 °C per decade · r² = 0.55 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
40.4 °C
15 August 2018
Coldest day
-21.7 °C
25 January 1941
Wettest day
183 mm
30 September 1998
Windiest day
46.0 km/h
28 August 2012
Strongest gust
119.9 km/h
28 August 1986
Hottest feels-like
44.3 °C
13 August 2018
Coldest feels-like
-27.1 °C
25 January 1941
Snowiest day
18.1 cm
5 March 2004
Sunniest day
14.1 h
28 June 1951
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | 4.8 °C | +2.2 °C | 14 mm | -11 mm |
| Feb | 4.5 °C | -0.7 °C | 10 mm | -21 mm |
| Mar | 13.9 °C | +2.8 °C | 50 mm | -3 mm |
| Apr | 20.6 °C | +2.3 °C | 60 mm | -23 mm |
| May | 23.3 °C | -0.3 °C | 90 mm | -1 mm |
| Jun | 29.0 °C | +1.8 °C | 250 mm | +114 mm |
| Jul | 32.3 °C | +3.3 °C | 219 mm | -49 mm |
| Aug | 31.9 °C | +2.0 °C | 122 mm | -84 mm |
| Sep | 27.2 °C | +1.6 °C | 279 mm | +132 mm |
| Oct | 21.0 °C | +1.1 °C | 209 mm | +155 mm |
| Nov | 14.7 °C | +2.3 °C | 11 mm | -34 mm |
| Dec | 6.5 °C | +1.4 °C | 34 mm | +7 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Sejong?
Sejong has a hot-summer humid continental, dry winter climate (Köppen Dwa). Over 1940-2025, the average annual temperature is 12.5 °C and it receives 1,166 mm of precipitation per year.
What is the hottest day ever recorded in Sejong?
The hottest day measured in Sejong between 1940 and 2025 was 15 August 2018, reaching 40.4 °C.
What is the coldest day in Sejong?
The coldest day measured in Sejong between 1940 and 2025 was 25 January 1941, at -21.7 °C.
Does it snow in Sejong?
Yes. Sejong gets on average 17.4 cm of snow per year and has around 103 frost days.
Has the climate of Sejong warmed?
Yes: Sejong warmed by +2.1 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Sejong?
The wettest day measured in Sejong between 1940 and 2025 was 30 September 1998, with 183 mm of rain in 24 hours.
What was the windiest day in Sejong?
The windiest day measured in Sejong between 1940 and 2025 was 28 August 2012, with winds reaching 46.0 km/h.
What is the warmest month in Sejong?
The warmest month in Sejong is August (25.8 °C on average); the coldest is January (-1.8 °C).
How much does it rain in Sejong?
Sejong receives on average 1,166 mm of precipitation per year, spread over about 99 rainy days.
Is it sunny in Sejong?
Sejong gets on average 8.8 hours of sunshine per day, roughly 3,212 hours per year over 1940-2025.
What is the biggest single-day snowfall in Sejong?
The heaviest 24-hour snowfall measured in Sejong between 1940 and 2025 was 5 March 2004, with 18.1 cm.
Are there tropical nights in Sejong?
Yes: Sejong has on average 61 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Sejong?
In Sejong, between 1940 and 2025, the highest apparent temperature reached 44.3 °C on 13 August 2018, and the lowest was -27.1 °C on 25 January 1941.
Compare Sejong with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Sejong