Semboku climate — normals and trends
Semboku (Japan) has a warm-summer humid continental climate (Dfb) under the Köppen-Geiger classification. Its mean annual temperature is 7.9 °C and it receives 1,892 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 (21.6 °C on average) and the coldest is January (-4.7 °C). Rainfall peaks in July.
Semboku averages 143 frost days, 2 hot days (≥ 30 °C) and 214 rainy days per year.
Semboku 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 159 to 127 per year over the period.
The hottest day of the period reached 33.1 °C (on 23 August 2018) and the coldest -20.1 °C (on 29 January 1947).
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
SembokuAkita
- coords
- 39.71°, 140.75°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
7.9°C
Average daily high
11.6°C
Average daily low
4.2°C
Annual rainfall
1,892mm
Sunshine / day
7.8h
Mean relative humidity
82%
Average peak wind
12.8km/h
Seasonal range
26.3°C
Frost days (< 0 °C)
143 d/yr
Hot days (≥ 30 °C)
2 d/yr
Rainy days (≥ 1 mm)
214 d/yr
Annual snowfall
305.7 cm
Average feels-like high
10.1 °C
Average feels-like low
2.3 °C
Average peak gust
42.7 km/h
Tropical nights (≥ 20 °C)
16 d/yr
Solar radiation
13.0 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.6 °C
since 1940
+0.3 °C per decade · r² = 0.63 · 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
33.1 °C
23 August 2018
Coldest day
-20.1 °C
29 January 1947
Wettest day
151 mm
23 July 1947
Windiest day
38.4 km/h
28 September 1991
Strongest gust
147.2 km/h
16 September 1961
Hottest feels-like
39.1 °C
23 August 2018
Coldest feels-like
-24.4 °C
9 February 1942
Snowiest day
42.2 cm
29 March 1966
Sunniest day
14.7 h
17 June 1942
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 | 0.3 °C | +2.0 °C | 117 mm | +3 mm |
| Feb | -0.2 °C | +0.6 °C | 94 mm | -10 mm |
| Mar | 4.4 °C | +1.3 °C | 145 mm | +10 mm |
| Apr | 10.3 °C | +0.7 °C | 181 mm | +45 mm |
| May | 17.4 °C | +1.1 °C | 178 mm | +37 mm |
| Jun | 23.9 °C | +3.8 °C | 171 mm | +6 mm |
| Jul | 28.8 °C | +5.2 °C | 72 mm | -181 mm |
| Aug | 27.7 °C | +2.5 °C | 231 mm | +13 mm |
| Sep | 23.5 °C | +2.6 °C | 283 mm | +78 mm |
| Oct | 15.3 °C | +0.6 °C | 128 mm | -18 mm |
| Nov | 8.1 °C | +0.4 °C | 179 mm | +41 mm |
| Dec | 2.0 °C | +0.9 °C | 173 mm | +36 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 Semboku?
Semboku has a warm-summer humid continental climate (Köppen Dfb). Over 1940-2025, the average annual temperature is 7.9 °C and it receives 1,892 mm of precipitation per year.
What is the hottest day ever recorded in Semboku?
The hottest day measured in Semboku between 1940 and 2025 was 23 August 2018, reaching 33.1 °C.
What is the coldest day in Semboku?
The coldest day measured in Semboku between 1940 and 2025 was 29 January 1947, at -20.1 °C.
Does it snow in Semboku?
Yes. Semboku gets on average 305.7 cm of snow per year and has around 143 frost days.
Has the climate of Semboku warmed?
Yes: Semboku warmed by +2.6 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Semboku?
The wettest day measured in Semboku between 1940 and 2025 was 23 July 1947, with 151 mm of rain in 24 hours.
What was the windiest day in Semboku?
The windiest day measured in Semboku between 1940 and 2025 was 28 September 1991, with winds reaching 38.4 km/h.
What is the warmest month in Semboku?
The warmest month in Semboku is August (21.6 °C on average); the coldest is January (-4.7 °C).
How much does it rain in Semboku?
Semboku receives on average 1,892 mm of precipitation per year, spread over about 214 rainy days.
Is it sunny in Semboku?
Semboku gets on average 7.8 hours of sunshine per day, roughly 2,847 hours per year over 1940-2025.
What is the biggest single-day snowfall in Semboku?
The heaviest 24-hour snowfall measured in Semboku between 1940 and 2025 was 29 March 1966, with 42.2 cm.
Are there tropical nights in Semboku?
Yes: Semboku has on average 16 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Semboku?
In Semboku, between 1940 and 2025, the highest apparent temperature reached 39.1 °C on 23 August 2018, and the lowest was -24.4 °C on 9 February 1942.
Compare Semboku with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Semboku