Hachimantai climate — normals and trends
Hachimantai (Japan) has a warm-summer humid continental climate (Dfb) under the Köppen-Geiger classification. Its mean annual temperature is 7.8 °C and it receives 1,170 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 (21.4 °C on average) and the coldest is January (-5.4 °C). Rainfall peaks in July.
Hachimantai averages 143 frost days, 3 hot days (≥ 30 °C) and 161 rainy days per year.
Hachimantai has warmed by +2.6 °C between 1940 and 2025, or +0.30 °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 33.8 °C (on 10 August 1999) and the coldest -22.3 °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
HachimantaiIwate
- coords
- 39.90°, 141.13°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
7.8°C
Average daily high
11.9°C
Average daily low
3.9°C
Annual rainfall
1,170mm
Sunshine / day
8.3h
Mean relative humidity
79%
Average peak wind
14.7km/h
Seasonal range
26.8°C
Frost days (< 0 °C)
143 d/yr
Hot days (≥ 30 °C)
3 d/yr
Rainy days (≥ 1 mm)
161 d/yr
Annual snowfall
186.6 cm
Average feels-like high
9.9 °C
Average feels-like low
1.5 °C
Average peak gust
42.1 km/h
Tropical nights (≥ 20 °C)
15 d/yr
Solar radiation
13.3 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
33.8 °C
10 August 1999
Coldest day
-22.3 °C
29 January 1947
Wettest day
126 mm
15 September 1947
Windiest day
46.3 km/h
28 September 1991
Strongest gust
135.4 km/h
28 September 1991
Hottest feels-like
38.4 °C
30 July 2025
Coldest feels-like
-27.1 °C
29 January 1947
Snowiest day
63.1 cm
29 March 1966
Sunniest day
14.8 h
14 June 1989
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 | 0.5 °C | +2.1 °C | 53 mm | -10 mm |
| Feb | -0.2 °C | +0.6 °C | 31 mm | -31 mm |
| Mar | 5.0 °C | +1.5 °C | 94 mm | +6 mm |
| Apr | 12.1 °C | +1.3 °C | 110 mm | +21 mm |
| May | 17.7 °C | +0.9 °C | 95 mm | +4 mm |
| Jun | 24.6 °C | +4.4 °C | 95 mm | -12 mm |
| Jul | 29.2 °C | +5.4 °C | 40 mm | -103 mm |
| Aug | 28.2 °C | +3.0 °C | 89 mm | -47 mm |
| Sep | 23.5 °C | +2.8 °C | 161 mm | +18 mm |
| Oct | 14.8 °C | +0.2 °C | 94 mm | -2 mm |
| Nov | 8.1 °C | +0.3 °C | 124 mm | +47 mm |
| Dec | 2.6 °C | +1.3 °C | 102 mm | +27 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 Hachimantai?
Hachimantai has a warm-summer humid continental climate (Köppen Dfb). Over 1940-2025, the average annual temperature is 7.8 °C and it receives 1,170 mm of precipitation per year.
What is the hottest day ever recorded in Hachimantai?
The hottest day measured in Hachimantai between 1940 and 2025 was 10 August 1999, reaching 33.8 °C.
What is the coldest day in Hachimantai?
The coldest day measured in Hachimantai between 1940 and 2025 was 29 January 1947, at -22.3 °C.
Does it snow in Hachimantai?
Yes. Hachimantai gets on average 186.6 cm of snow per year and has around 143 frost days.
Has the climate of Hachimantai warmed?
Yes: Hachimantai warmed by +2.6 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Hachimantai?
The wettest day measured in Hachimantai between 1940 and 2025 was 15 September 1947, with 126 mm of rain in 24 hours.
What was the windiest day in Hachimantai?
The windiest day measured in Hachimantai between 1940 and 2025 was 28 September 1991, with winds reaching 46.3 km/h.
What is the warmest month in Hachimantai?
The warmest month in Hachimantai is August (21.4 °C on average); the coldest is January (-5.4 °C).
How much does it rain in Hachimantai?
Hachimantai receives on average 1,170 mm of precipitation per year, spread over about 161 rainy days.
Is it sunny in Hachimantai?
Hachimantai gets on average 8.3 hours of sunshine per day, roughly 3,030 hours per year over 1940-2025.
What is the biggest single-day snowfall in Hachimantai?
The heaviest 24-hour snowfall measured in Hachimantai between 1940 and 2025 was 29 March 1966, with 63.1 cm.
Are there tropical nights in Hachimantai?
Yes: Hachimantai has on average 15 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Hachimantai?
In Hachimantai, between 1940 and 2025, the highest apparent temperature reached 38.4 °C on 30 July 2025, and the lowest was -27.1 °C on 29 January 1947.
Compare Hachimantai with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Hachimantai