Kōzan climate — normals and trends
Kōzan (Japan) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 14.9 °C and it receives 1,327 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 (27.0 °C on average) and the coldest is January (3.6 °C). Rainfall peaks in July.
Kōzan averages 47 frost days, 43 hot days (≥ 30 °C) and 119 rainy days per year.
Kōzan has warmed by +2.7 °C between 1940 and 2025, or +0.32 °C per decade. This trend is statistically significant.
The number of frost days there went from about 70 to 24 per year over the period.
The hottest day of the period reached 38.5 °C (on 4 August 2001) and the coldest -10.9 °C (on 18 February 1977).
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
KōzanHiroshima
- coords
- 34.58°, 133.05°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
14.9°C
Average daily high
19.3°C
Average daily low
10.8°C
Annual rainfall
1,327mm
Sunshine / day
8.7h
Mean relative humidity
73%
Average peak wind
13.8km/h
Seasonal range
23.4°C
Frost days (< 0 °C)
47 d/yr
Hot days (≥ 30 °C)
43 d/yr
Rainy days (≥ 1 mm)
119 d/yr
Annual snowfall
11.1 cm
Average feels-like high
18.9 °C
Average feels-like low
9.9 °C
Average peak gust
34.2 km/h
Tropical nights (≥ 20 °C)
78 d/yr
Solar radiation
14.6 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.7 °C
since 1940
+0.3 °C per decade · r² = 0.70 · 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
38.5 °C
4 August 2001
Coldest day
-10.9 °C
18 February 1977
Wettest day
176 mm
14 August 2021
Windiest day
60.4 km/h
27 September 1991
Strongest gust
154.8 km/h
7 September 2004
Hottest feels-like
43.5 °C
4 August 2001
Coldest feels-like
-15.7 °C
18 February 1977
Snowiest day
24.2 cm
15 February 1968
Sunniest day
14.0 h
27 May 1940
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 | 8.0 °C | +0.3 °C | 14 mm | -25 mm |
| Feb | 6.4 °C | -2.3 °C | 39 mm | -17 mm |
| Mar | 13.6 °C | +0.9 °C | 115 mm | +27 mm |
| Apr | 19.5 °C | +1.1 °C | 56 mm | -57 mm |
| May | 22.8 °C | +0.1 °C | 173 mm | +42 mm |
| Jun | 27.6 °C | +1.9 °C | 267 mm | +64 mm |
| Jul | 33.0 °C | +3.5 °C | 50 mm | -155 mm |
| Aug | 32.5 °C | +1.4 °C | 168 mm | +34 mm |
| Sep | 29.0 °C | +1.8 °C | 200 mm | +34 mm |
| Oct | 23.2 °C | +1.6 °C | 137 mm | +43 mm |
| Nov | 16.3 °C | +0.4 °C | 22 mm | -39 mm |
| Dec | 10.8 °C | +0.5 °C | 35 mm | -5 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 Kōzan?
Kōzan has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 14.9 °C and it receives 1,327 mm of precipitation per year.
What is the hottest day ever recorded in Kōzan?
The hottest day measured in Kōzan between 1940 and 2025 was 4 August 2001, reaching 38.5 °C.
What is the coldest day in Kōzan?
The coldest day measured in Kōzan between 1940 and 2025 was 18 February 1977, at -10.9 °C.
Does it snow in Kōzan?
Yes. Kōzan gets on average 11.1 cm of snow per year and has around 47 frost days.
Has the climate of Kōzan warmed?
Yes: Kōzan warmed by +2.7 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Kōzan?
The wettest day measured in Kōzan between 1940 and 2025 was 14 August 2021, with 176 mm of rain in 24 hours.
What was the windiest day in Kōzan?
The windiest day measured in Kōzan between 1940 and 2025 was 27 September 1991, with winds reaching 60.4 km/h.
What is the warmest month in Kōzan?
The warmest month in Kōzan is August (27.0 °C on average); the coldest is January (3.6 °C).
How much does it rain in Kōzan?
Kōzan receives on average 1,327 mm of precipitation per year, spread over about 119 rainy days.
Is it sunny in Kōzan?
Kōzan gets on average 8.7 hours of sunshine per day, roughly 3,175 hours per year over 1940-2025.
What is the biggest single-day snowfall in Kōzan?
The heaviest 24-hour snowfall measured in Kōzan between 1940 and 2025 was 15 February 1968, with 24.2 cm.
Are there tropical nights in Kōzan?
Yes: Kōzan has on average 78 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Kōzan?
In Kōzan, between 1940 and 2025, the highest apparent temperature reached 43.5 °C on 4 August 2001, and the lowest was -15.7 °C on 18 February 1977.
Compare Kōzan with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Kōzan