Rumoi climate — normals and trends
Rumoi (Japan) has a warm-summer humid continental climate (Dfb) under the Köppen-Geiger classification. Its mean annual temperature is 6.9 °C and it receives 1,153 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 (21.0 °C on average) and the coldest is January (-6.6 °C). Rainfall peaks in August.
Rumoi averages 141 frost days, 0 hot days (≥ 30 °C) and 185 rainy days per year.
Rumoi has warmed by +2.3 °C between 1940 and 2025, or +0.27 °C per decade. This trend is statistically significant.
The number of frost days there went from about 156 to 126 per year over the period.
The hottest day of the period reached 32.0 °C (on 23 August 2023) and the coldest -22.3 °C (on 25 January 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
RumoiHokkaido
- coords
- 43.93°, 141.64°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
6.9°C
Average daily high
9.8°C
Average daily low
3.9°C
Annual rainfall
1,153mm
Sunshine / day
8.5h
Mean relative humidity
78%
Average peak wind
17.7km/h
Seasonal range
27.6°C
Frost days (< 0 °C)
141 d/yr
Hot days (≥ 30 °C)
0 d/yr
Rainy days (≥ 1 mm)
185 d/yr
Annual snowfall
251.5 cm
Average feels-like high
7.7 °C
Average feels-like low
1.1 °C
Average peak gust
38.3 km/h
Tropical nights (≥ 20 °C)
14 d/yr
Solar radiation
13.2 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.3 °C
since 1940
+0.3 °C per decade · r² = 0.62 · 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
32.0 °C
23 August 2023
Coldest day
-22.3 °C
25 January 1985
Wettest day
178 mm
3 August 1962
Windiest day
61.7 km/h
8 September 2004
Strongest gust
136.8 km/h
27 September 1954
Hottest feels-like
38.8 °C
24 August 2023
Coldest feels-like
-27.2 °C
25 January 1985
Snowiest day
23.9 cm
5 December 2004
Sunniest day
15.0 h
29 June 1940
Normals computed over complete calendar years 1940–2025.
A specific year
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Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | -1.2 °C | +2.7 °C | 64 mm | -5 mm |
| Feb | 0.0 °C | +2.9 °C | 67 mm | +7 mm |
| Mar | 2.3 °C | +0.9 °C | 100 mm | +31 mm |
| Apr | 9.2 °C | +1.2 °C | 120 mm | +48 mm |
| May | 16.1 °C | +2.6 °C | 69 mm | -13 mm |
| Jun | 21.4 °C | +3.8 °C | 95 mm | +20 mm |
| Jul | 27.5 °C | +5.3 °C | 87 mm | -21 mm |
| Aug | 26.5 °C | +2.8 °C | 197 mm | +52 mm |
| Sep | 22.9 °C | +3.0 °C | 182 mm | +48 mm |
| Oct | 13.3 °C | -0.2 °C | 121 mm | +2 mm |
| Nov | 6.9 °C | +1.0 °C | 172 mm | +52 mm |
| Dec | 1.3 °C | +2.1 °C | 150 mm | +49 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 Rumoi?
Rumoi has a warm-summer humid continental climate (Köppen Dfb). Over 1940-2025, the average annual temperature is 6.9 °C and it receives 1,153 mm of precipitation per year.
What is the hottest day ever recorded in Rumoi?
The hottest day measured in Rumoi between 1940 and 2025 was 23 August 2023, reaching 32.0 °C.
What is the coldest day in Rumoi?
The coldest day measured in Rumoi between 1940 and 2025 was 25 January 1985, at -22.3 °C.
Does it snow in Rumoi?
Yes. Rumoi gets on average 251.5 cm of snow per year and has around 141 frost days.
Has the climate of Rumoi warmed?
Yes: Rumoi warmed by +2.3 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Rumoi?
The wettest day measured in Rumoi between 1940 and 2025 was 3 August 1962, with 178 mm of rain in 24 hours.
What was the windiest day in Rumoi?
The windiest day measured in Rumoi between 1940 and 2025 was 8 September 2004, with winds reaching 61.7 km/h.
What is the warmest month in Rumoi?
The warmest month in Rumoi is August (21.0 °C on average); the coldest is January (-6.6 °C).
How much does it rain in Rumoi?
Rumoi receives on average 1,153 mm of precipitation per year, spread over about 185 rainy days.
Is it sunny in Rumoi?
Rumoi gets on average 8.5 hours of sunshine per day, roughly 3,103 hours per year over 1940-2025.
What is the biggest single-day snowfall in Rumoi?
The heaviest 24-hour snowfall measured in Rumoi between 1940 and 2025 was 5 December 2004, with 23.9 cm.
Are there tropical nights in Rumoi?
Yes: Rumoi has on average 14 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Rumoi?
In Rumoi, between 1940 and 2025, the highest apparent temperature reached 38.8 °C on 24 August 2023, and the lowest was -27.2 °C on 25 January 1985.
Compare Rumoi with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Rumoi