Ōwa climate — normals and trends
Ōwa (Japan) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 14.1 °C and it receives 1,606 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 (26.0 °C on average) and the coldest is January (2.7 °C). Rainfall peaks in September.
Ōwa averages 59 frost days, 34 hot days (≥ 30 °C) and 153 rainy days per year.
Ōwa has warmed by +2.6 °C between 1940 and 2025, or +0.31 °C per decade. This trend is statistically significant.
The number of frost days there went from about 85 to 33 per year over the period.
The hottest day of the period reached 38.1 °C (on 5 August 2025) and the coldest -16.6 °C (on 16 February 1967).
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
ŌwaGunma
- coords
- 36.20°, 139.49°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
14.1°C
Average daily high
18.4°C
Average daily low
10.3°C
Annual rainfall
1,606mm
Sunshine / day
8.2h
Mean relative humidity
73%
Average peak wind
12.3km/h
Seasonal range
23.3°C
Frost days (< 0 °C)
59 d/yr
Hot days (≥ 30 °C)
34 d/yr
Rainy days (≥ 1 mm)
153 d/yr
Annual snowfall
26.5 cm
Average feels-like high
18.2 °C
Average feels-like low
9.6 °C
Average peak gust
27.1 km/h
Tropical nights (≥ 20 °C)
71 d/yr
Solar radiation
13.5 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.6 °C
since 1940
+0.3 °C per decade · r² = 0.68 · 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
38.1 °C
5 August 2025
Coldest day
-16.6 °C
16 February 1967
Wettest day
225 mm
26 September 1958
Windiest day
57.5 km/h
16 September 1961
Strongest gust
141.8 km/h
27 September 1959
Hottest feels-like
44.8 °C
16 August 2007
Coldest feels-like
-21.4 °C
16 February 1967
Snowiest day
30.3 cm
15 January 1998
Sunniest day
14.0 h
26 June 1946
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 | 9.7 °C | +2.2 °C | 33 mm | -10 mm |
| Feb | 9.3 °C | +1.0 °C | 6 mm | -48 mm |
| Mar | 14.2 °C | +2.2 °C | 153 mm | +56 mm |
| Apr | 19.3 °C | +1.7 °C | 136 mm | +17 mm |
| May | 22.2 °C | +0.1 °C | 206 mm | +55 mm |
| Jun | 28.5 °C | +3.8 °C | 153 mm | -47 mm |
| Jul | 32.7 °C | +4.3 °C | 80 mm | -135 mm |
| Aug | 33.7 °C | +3.9 °C | 79 mm | -112 mm |
| Sep | 29.4 °C | +3.7 °C | 180 mm | -49 mm |
| Oct | 20.9 °C | +0.8 °C | 124 mm | -53 mm |
| Nov | 16.2 °C | +1.3 °C | 21 mm | -63 mm |
| Dec | 11.3 °C | +1.3 °C | 58 mm | +11 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 Ōwa?
Ōwa has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 14.1 °C and it receives 1,606 mm of precipitation per year.
What is the hottest day ever recorded in Ōwa?
The hottest day measured in Ōwa between 1940 and 2025 was 5 August 2025, reaching 38.1 °C.
What is the coldest day in Ōwa?
The coldest day measured in Ōwa between 1940 and 2025 was 16 February 1967, at -16.6 °C.
Does it snow in Ōwa?
Yes. Ōwa gets on average 26.5 cm of snow per year and has around 59 frost days.
Has the climate of Ōwa warmed?
Yes: Ōwa warmed by +2.6 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Ōwa?
The wettest day measured in Ōwa between 1940 and 2025 was 26 September 1958, with 225 mm of rain in 24 hours.
What was the windiest day in Ōwa?
The windiest day measured in Ōwa between 1940 and 2025 was 16 September 1961, with winds reaching 57.5 km/h.
What is the warmest month in Ōwa?
The warmest month in Ōwa is August (26.0 °C on average); the coldest is January (2.7 °C).
How much does it rain in Ōwa?
Ōwa receives on average 1,606 mm of precipitation per year, spread over about 153 rainy days.
Is it sunny in Ōwa?
Ōwa gets on average 8.2 hours of sunshine per day, roughly 2,993 hours per year over 1940-2025.
What is the biggest single-day snowfall in Ōwa?
The heaviest 24-hour snowfall measured in Ōwa between 1940 and 2025 was 15 January 1998, with 30.3 cm.
Are there tropical nights in Ōwa?
Yes: Ōwa has on average 71 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Ōwa?
In Ōwa, between 1940 and 2025, the highest apparent temperature reached 44.8 °C on 16 August 2007, and the lowest was -21.4 °C on 16 February 1967.
Compare Ōwa with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Ōwa