Ōshū climate — normals and trends
Ōshū (Japan) has a hot-summer humid continental climate (Dfa) under the Köppen-Geiger classification. Its mean annual temperature is 9.1 °C and it receives 1,272 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 (22.4 °C on average) and the coldest is January (-3.9 °C). Rainfall peaks in July.
Ōshū averages 132 frost days, 6 hot days (≥ 30 °C) and 162 rainy days per year.
Ōshū has warmed by +3.1 °C between 1940 and 2025, or +0.36 °C per decade. This trend is statistically significant.
The number of frost days there went from about 150 to 114 per year over the period.
The hottest day of the period reached 34.3 °C (on 14 August 2007) and the coldest -25.1 °C (on 16 December 1985).
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
ŌshūIwate
- coords
- 39.14°, 141.17°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
9.1°C
Average daily high
13.3°C
Average daily low
4.9°C
Annual rainfall
1,272mm
Sunshine / day
8.2h
Mean relative humidity
79%
Average peak wind
14.9km/h
Seasonal range
26.3°C
Frost days (< 0 °C)
132 d/yr
Hot days (≥ 30 °C)
6 d/yr
Rainy days (≥ 1 mm)
162 d/yr
Annual snowfall
125.2 cm
Average feels-like high
11.7 °C
Average feels-like low
3.0 °C
Average peak gust
42.5 km/h
Tropical nights (≥ 20 °C)
23 d/yr
Solar radiation
13.4 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+3.1 °C
since 1940
+0.4 °C per decade · r² = 0.69 · 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
34.3 °C
14 August 2007
Coldest day
-25.1 °C
16 December 1985
Wettest day
146 mm
21 August 1991
Windiest day
44.6 km/h
31 March 1979
Strongest gust
129.6 km/h
23 August 1981
Hottest feels-like
40.7 °C
23 August 2018
Coldest feels-like
-29.6 °C
16 December 1985
Snowiest day
39.1 cm
18 January 2016
Sunniest day
14.7 h
18 June 1987
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 | 2.7 °C | +2.4 °C | 48 mm | -11 mm |
| Feb | 2.3 °C | +1.2 °C | 32 mm | -27 mm |
| Mar | 7.9 °C | +2.6 °C | 86 mm | -2 mm |
| Apr | 13.4 °C | +0.9 °C | 121 mm | +22 mm |
| May | 18.5 °C | +0.7 °C | 147 mm | +40 mm |
| Jun | 25.3 °C | +4.3 °C | 100 mm | -25 mm |
| Jul | 29.6 °C | +5.0 °C | 93 mm | -73 mm |
| Aug | 28.8 °C | +2.6 °C | 141 mm | -12 mm |
| Sep | 24.6 °C | +2.7 °C | 178 mm | +17 mm |
| Oct | 16.5 °C | +0.5 °C | 115 mm | +5 mm |
| Nov | 10.1 °C | +0.6 °C | 85 mm | +7 mm |
| Dec | 4.5 °C | +1.4 °C | 84 mm | +15 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 Ōshū?
Ōshū has a hot-summer humid continental climate (Köppen Dfa). Over 1940-2025, the average annual temperature is 9.1 °C and it receives 1,272 mm of precipitation per year.
What is the hottest day ever recorded in Ōshū?
The hottest day measured in Ōshū between 1940 and 2025 was 14 August 2007, reaching 34.3 °C.
What is the coldest day in Ōshū?
The coldest day measured in Ōshū between 1940 and 2025 was 16 December 1985, at -25.1 °C.
Does it snow in Ōshū?
Yes. Ōshū gets on average 125.2 cm of snow per year and has around 132 frost days.
Has the climate of Ōshū warmed?
Yes: Ōshū warmed by +3.1 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Ōshū?
The wettest day measured in Ōshū between 1940 and 2025 was 21 August 1991, with 146 mm of rain in 24 hours.
What was the windiest day in Ōshū?
The windiest day measured in Ōshū between 1940 and 2025 was 31 March 1979, with winds reaching 44.6 km/h.
What is the warmest month in Ōshū?
The warmest month in Ōshū is August (22.4 °C on average); the coldest is January (-3.9 °C).
How much does it rain in Ōshū?
Ōshū receives on average 1,272 mm of precipitation per year, spread over about 162 rainy days.
Is it sunny in Ōshū?
Ōshū 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 Ōshū?
The heaviest 24-hour snowfall measured in Ōshū between 1940 and 2025 was 18 January 2016, with 39.1 cm.
Are there tropical nights in Ōshū?
Yes: Ōshū has on average 23 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Ōshū?
In Ōshū, between 1940 and 2025, the highest apparent temperature reached 40.7 °C on 23 August 2018, and the lowest was -29.6 °C on 16 December 1985.
Compare Ōshū with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Ōshū