Otaru climate — normals and trends
Otaru (Japan) has a warm-summer humid continental climate (Dfb) under the Köppen-Geiger classification. Its mean annual temperature is 7.0 °C and it receives 1,276 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 (20.8 °C on average) and the coldest is January (-5.1 °C). Rainfall peaks in August.
Otaru averages 135 frost days, 0 hot days (≥ 30 °C) and 193 rainy days per year.
Otaru has warmed by +2.3 °C between 1940 and 2025, or +0.28 °C per decade. This trend is statistically significant.
The number of frost days there went from about 152 to 118 per year over the period.
The hottest day of the period reached 30.3 °C (on 23 August 2023) and the coldest -15.2 °C (on 19 January 1966).
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
OtaruHokkaido
- coords
- 43.19°, 141.00°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
7.0°C
Average daily high
9.1°C
Average daily low
4.9°C
Annual rainfall
1,276mm
Sunshine / day
8.7h
Mean relative humidity
79%
Average peak wind
20.2km/h
Seasonal range
25.9°C
Frost days (< 0 °C)
135 d/yr
Hot days (≥ 30 °C)
0 d/yr
Rainy days (≥ 1 mm)
193 d/yr
Annual snowfall
297.2 cm
Average feels-like high
6.9 °C
Average feels-like low
1.6 °C
Average peak gust
40.2 km/h
Tropical nights (≥ 20 °C)
15 d/yr
Solar radiation
13.4 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.3 °C
since 1940
+0.3 °C per decade · r² = 0.63 · 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
30.3 °C
23 August 2023
Coldest day
-15.2 °C
19 January 1966
Wettest day
124 mm
17 August 2016
Windiest day
64.4 km/h
27 September 1954
Strongest gust
141.1 km/h
27 September 1954
Hottest feels-like
37.0 °C
24 August 2023
Coldest feels-like
-24.0 °C
12 January 1979
Snowiest day
33.5 cm
5 December 2004
Sunniest day
15.0 h
10 June 1940
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 | -0.8 °C | +2.6 °C | 124 mm | +29 mm |
| Feb | 0.1 °C | +2.9 °C | 132 mm | +51 mm |
| Mar | 2.5 °C | +1.6 °C | 115 mm | +36 mm |
| Apr | 8.0 °C | +1.8 °C | 98 mm | +24 mm |
| May | 14.5 °C | +2.9 °C | 58 mm | -25 mm |
| Jun | 20.1 °C | +3.9 °C | 93 mm | +11 mm |
| Jul | 25.7 °C | +5.0 °C | 100 mm | -13 mm |
| Aug | 25.4 °C | +2.6 °C | 189 mm | +31 mm |
| Sep | 22.4 °C | +3.0 °C | 207 mm | +58 mm |
| Oct | 13.2 °C | +0.1 °C | 139 mm | +14 mm |
| Nov | 7.0 °C | +1.5 °C | 185 mm | +62 mm |
| Dec | 1.0 °C | +1.7 °C | 167 mm | +52 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 Otaru?
Otaru has a warm-summer humid continental climate (Köppen Dfb). Over 1940-2025, the average annual temperature is 7.0 °C and it receives 1,276 mm of precipitation per year.
What is the hottest day ever recorded in Otaru?
The hottest day measured in Otaru between 1940 and 2025 was 23 August 2023, reaching 30.3 °C.
What is the coldest day in Otaru?
The coldest day measured in Otaru between 1940 and 2025 was 19 January 1966, at -15.2 °C.
Does it snow in Otaru?
Yes. Otaru gets on average 297.2 cm of snow per year and has around 135 frost days.
Has the climate of Otaru warmed?
Yes: Otaru warmed by +2.3 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Otaru?
The wettest day measured in Otaru between 1940 and 2025 was 17 August 2016, with 124 mm of rain in 24 hours.
What was the windiest day in Otaru?
The windiest day measured in Otaru between 1940 and 2025 was 27 September 1954, with winds reaching 64.4 km/h.
What is the warmest month in Otaru?
The warmest month in Otaru is August (20.8 °C on average); the coldest is January (-5.1 °C).
How much does it rain in Otaru?
Otaru receives on average 1,276 mm of precipitation per year, spread over about 193 rainy days.
Is it sunny in Otaru?
Otaru gets on average 8.7 hours of sunshine per day, roughly 3,175 hours per year over 1940-2025.
What is the biggest single-day snowfall in Otaru?
The heaviest 24-hour snowfall measured in Otaru between 1940 and 2025 was 5 December 2004, with 33.5 cm.
Are there tropical nights in Otaru?
Yes: Otaru has on average 15 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Otaru?
In Otaru, between 1940 and 2025, the highest apparent temperature reached 37.0 °C on 24 August 2023, and the lowest was -24.0 °C on 12 January 1979.
Compare Otaru with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Otaru