Bizen climate — normals and trends
Bizen (Japan) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 15.7 °C and it receives 1,433 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 (26.6 °C on average) and the coldest is January (5.8 °C). Rainfall peaks in June.
Bizen averages 3 frost days, 7 hot days (≥ 30 °C) and 121 rainy days per year.
Bizen has warmed by +1.3 °C between 1940 and 2025, or +0.15 °C per decade. This trend is statistically significant.
The number of frost days there went from about 5 to 1 per year over the period.
The hottest day of the period reached 33.3 °C (on 2 August 2002) and the coldest -3.9 °C (on 16 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
BizenOkayama
- coords
- 34.79°, 134.24°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
15.7°C
Average daily high
18.1°C
Average daily low
13.5°C
Annual rainfall
1,433mm
Sunshine / day
9.0h
Mean relative humidity
74%
Average peak wind
21.1km/h
Seasonal range
20.8°C
Frost days (< 0 °C)
3 d/yr
Hot days (≥ 30 °C)
7 d/yr
Rainy days (≥ 1 mm)
121 d/yr
Annual snowfall
3.7 cm
Average feels-like high
17.6 °C
Average feels-like low
12.0 °C
Average peak gust
34.2 km/h
Tropical nights (≥ 20 °C)
97 d/yr
Solar radiation
15.4 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.3 °C
since 1940
+0.2 °C per decade · r² = 0.52 · 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
33.3 °C
2 August 2002
Coldest day
-3.9 °C
16 February 1977
Wettest day
226 mm
27 October 1961
Windiest day
80.5 km/h
14 September 1954
Strongest gust
154.8 km/h
4 September 1993
Hottest feels-like
40.0 °C
11 August 2013
Coldest feels-like
-12.3 °C
26 February 1981
Snowiest day
13.0 cm
12 February 1994
Sunniest day
14.0 h
21 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 | 8.4 °C | +0.1 °C | 13 mm | -32 mm |
| Feb | 7.1 °C | -1.7 °C | 25 mm | -36 mm |
| Mar | 11.2 °C | -0.6 °C | 109 mm | +9 mm |
| Apr | 15.9 °C | -0.4 °C | 54 mm | -76 mm |
| May | 19.7 °C | -0.1 °C | 184 mm | +35 mm |
| Jun | 24.3 °C | +1.3 °C | 233 mm | +32 mm |
| Jul | 29.0 °C | +2.2 °C | 69 mm | -121 mm |
| Aug | 30.6 °C | +2.1 °C | 125 mm | +2 mm |
| Sep | 28.3 °C | +2.4 °C | 253 mm | +63 mm |
| Oct | 22.9 °C | +1.9 °C | 212 mm | +86 mm |
| Nov | 16.4 °C | +0.5 °C | 29 mm | -45 mm |
| Dec | 11.7 °C | +0.8 °C | 37 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 Bizen?
Bizen has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 15.7 °C and it receives 1,433 mm of precipitation per year.
What is the hottest day ever recorded in Bizen?
The hottest day measured in Bizen between 1940 and 2025 was 2 August 2002, reaching 33.3 °C.
What is the coldest day in Bizen?
The coldest day measured in Bizen between 1940 and 2025 was 16 February 1977, at -3.9 °C.
Does it snow in Bizen?
Yes. Bizen gets on average 3.7 cm of snow per year and has around 3 frost days.
Has the climate of Bizen warmed?
Yes: Bizen warmed by +1.3 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Bizen?
The wettest day measured in Bizen between 1940 and 2025 was 27 October 1961, with 226 mm of rain in 24 hours.
What was the windiest day in Bizen?
The windiest day measured in Bizen between 1940 and 2025 was 14 September 1954, with winds reaching 80.5 km/h.
What is the warmest month in Bizen?
The warmest month in Bizen is August (26.6 °C on average); the coldest is January (5.8 °C).
How much does it rain in Bizen?
Bizen receives on average 1,433 mm of precipitation per year, spread over about 121 rainy days.
Is it sunny in Bizen?
Bizen gets on average 9.0 hours of sunshine per day, roughly 3,285 hours per year over 1940-2025.
What is the biggest single-day snowfall in Bizen?
The heaviest 24-hour snowfall measured in Bizen between 1940 and 2025 was 12 February 1994, with 13.0 cm.
Are there tropical nights in Bizen?
Yes: Bizen has on average 97 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Bizen?
In Bizen, between 1940 and 2025, the highest apparent temperature reached 40.0 °C on 11 August 2013, and the lowest was -12.3 °C on 26 February 1981.
Compare Bizen with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Bizen