Koesan climate — normals and trends
Koesan (South Korea) has a hot-summer humid continental, dry winter climate (Dwa) under the Köppen-Geiger classification. Its mean annual temperature is 11.6 °C and it receives 1,187 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 (25.0 °C on average) and the coldest is January (-3.2 °C). Rainfall peaks in July.
Koesan averages 110 frost days, 27 hot days (≥ 30 °C) and 104 rainy days per year.
Koesan 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 122 to 98 per year over the period.
The hottest day of the period reached 37.6 °C (on 15 August 2018) and the coldest -23.5 °C (on 13 January 1951).
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
KoesanNorth Chungcheong
- coords
- 36.81°, 127.79°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
11.6°C
Average daily high
16.5°C
Average daily low
7.2°C
Annual rainfall
1,187mm
Sunshine / day
8.6h
Mean relative humidity
69%
Average peak wind
14.3km/h
Seasonal range
28.2°C
Frost days (< 0 °C)
110 d/yr
Hot days (≥ 30 °C)
27 d/yr
Rainy days (≥ 1 mm)
104 d/yr
Annual snowfall
26.4 cm
Average feels-like high
15.3 °C
Average feels-like low
5.5 °C
Average peak gust
35.4 km/h
Tropical nights (≥ 20 °C)
52 d/yr
Solar radiation
14.8 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
37.6 °C
15 August 2018
Coldest day
-23.5 °C
13 January 1951
Wettest day
169 mm
19 August 1972
Windiest day
43.6 km/h
28 August 2012
Strongest gust
130.0 km/h
28 August 1986
Hottest feels-like
42.8 °C
13 August 1952
Coldest feels-like
-29.0 °C
13 January 1951
Snowiest day
23.9 cm
5 March 2004
Sunniest day
14.1 h
20 June 1944
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 | 3.5 °C | +2.1 °C | 15 mm | -11 mm |
| Feb | 3.4 °C | -0.8 °C | 10 mm | -22 mm |
| Mar | 12.9 °C | +2.7 °C | 58 mm | -2 mm |
| Apr | 19.5 °C | +2.1 °C | 73 mm | -15 mm |
| May | 22.3 °C | -0.4 °C | 93 mm | -2 mm |
| Jun | 28.4 °C | +2.2 °C | 242 mm | +104 mm |
| Jul | 31.5 °C | +3.3 °C | 208 mm | -65 mm |
| Aug | 31.2 °C | +2.2 °C | 105 mm | -97 mm |
| Sep | 26.3 °C | +1.7 °C | 254 mm | +109 mm |
| Oct | 20.0 °C | +1.2 °C | 201 mm | +147 mm |
| Nov | 13.7 °C | +2.4 °C | 12 mm | -34 mm |
| Dec | 5.4 °C | +1.5 °C | 38 mm | +9 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 Koesan?
Koesan has a hot-summer humid continental, dry winter climate (Köppen Dwa). Over 1940-2025, the average annual temperature is 11.6 °C and it receives 1,187 mm of precipitation per year.
What is the hottest day ever recorded in Koesan?
The hottest day measured in Koesan between 1940 and 2025 was 15 August 2018, reaching 37.6 °C.
What is the coldest day in Koesan?
The coldest day measured in Koesan between 1940 and 2025 was 13 January 1951, at -23.5 °C.
Does it snow in Koesan?
Yes. Koesan gets on average 26.4 cm of snow per year and has around 110 frost days.
Has the climate of Koesan warmed?
Yes: Koesan warmed by +2.1 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Koesan?
The wettest day measured in Koesan between 1940 and 2025 was 19 August 1972, with 169 mm of rain in 24 hours.
What was the windiest day in Koesan?
The windiest day measured in Koesan between 1940 and 2025 was 28 August 2012, with winds reaching 43.6 km/h.
What is the warmest month in Koesan?
The warmest month in Koesan is August (25.0 °C on average); the coldest is January (-3.2 °C).
How much does it rain in Koesan?
Koesan receives on average 1,187 mm of precipitation per year, spread over about 104 rainy days.
Is it sunny in Koesan?
Koesan gets on average 8.6 hours of sunshine per day, roughly 3,139 hours per year over 1940-2025.
What is the biggest single-day snowfall in Koesan?
The heaviest 24-hour snowfall measured in Koesan between 1940 and 2025 was 5 March 2004, with 23.9 cm.
Are there tropical nights in Koesan?
Yes: Koesan has on average 52 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Koesan?
In Koesan, between 1940 and 2025, the highest apparent temperature reached 42.8 °C on 13 August 1952, and the lowest was -29.0 °C on 13 January 1951.
Compare Koesan with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Koesan