Asso climate — normals and trends
Asso (Japan) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 15.3 °C and it receives 2,231 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 (25.6 °C on average) and the coldest is January (5.3 °C). Rainfall peaks in June.
Asso averages 9 frost days, 10 hot days (≥ 30 °C) and 161 rainy days per year.
Asso has warmed by +2.0 °C between 1940 and 2025, or +0.24 °C per decade. This trend is statistically significant.
The number of frost days there went from about 19 to 0 per year over the period.
The hottest day of the period reached 34.5 °C (on 17 August 2020) and the coldest -5.4 °C (on 9 February 1940).
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
AssoWakayama
- coords
- 33.70°, 135.42°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
15.3°C
Average daily high
18.3°C
Average daily low
12.5°C
Annual rainfall
2,231mm
Sunshine / day
9.0h
Mean relative humidity
76%
Average peak wind
19.4km/h
Seasonal range
20.3°C
Frost days (< 0 °C)
9 d/yr
Hot days (≥ 30 °C)
10 d/yr
Rainy days (≥ 1 mm)
161 d/yr
Annual snowfall
7.4 cm
Average feels-like high
17.9 °C
Average feels-like low
11.1 °C
Average peak gust
40.8 km/h
Tropical nights (≥ 20 °C)
89 d/yr
Solar radiation
15.1 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.0 °C
since 1940
+0.2 °C per decade · r² = 0.65 · 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
34.5 °C
17 August 2020
Coldest day
-5.4 °C
9 February 1940
Wettest day
229 mm
19 July 2011
Windiest day
77.1 km/h
26 September 1959
Strongest gust
188.6 km/h
26 September 1959
Hottest feels-like
39.6 °C
16 July 1994
Coldest feels-like
-12.4 °C
26 February 1981
Snowiest day
11.0 cm
10 February 1972
Sunniest day
14.0 h
28 May 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 | 8.7 °C | +0.5 °C | 50 mm | -38 mm |
| Feb | 7.2 °C | -1.6 °C | 52 mm | -53 mm |
| Mar | 13.7 °C | +1.5 °C | 124 mm | -27 mm |
| Apr | 17.9 °C | +0.8 °C | 128 mm | -61 mm |
| May | 21.0 °C | +0.2 °C | 347 mm | +128 mm |
| Jun | 25.6 °C | +1.9 °C | 238 mm | -102 mm |
| Jul | 29.3 °C | +2.1 °C | 164 mm | -130 mm |
| Aug | 29.8 °C | +1.4 °C | 156 mm | -51 mm |
| Sep | 28.1 °C | +2.3 °C | 178 mm | -62 mm |
| Oct | 22.7 °C | +1.7 °C | 289 mm | +97 mm |
| Nov | 16.5 °C | +0.4 °C | 68 mm | -55 mm |
| Dec | 12.2 °C | +1.4 °C | 72 mm | -11 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 Asso?
Asso has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 15.3 °C and it receives 2,231 mm of precipitation per year.
What is the hottest day ever recorded in Asso?
The hottest day measured in Asso between 1940 and 2025 was 17 August 2020, reaching 34.5 °C.
What is the coldest day in Asso?
The coldest day measured in Asso between 1940 and 2025 was 9 February 1940, at -5.4 °C.
Does it snow in Asso?
Yes. Asso gets on average 7.4 cm of snow per year and has around 9 frost days.
Has the climate of Asso warmed?
Yes: Asso warmed by +2.0 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Asso?
The wettest day measured in Asso between 1940 and 2025 was 19 July 2011, with 229 mm of rain in 24 hours.
What was the windiest day in Asso?
The windiest day measured in Asso between 1940 and 2025 was 26 September 1959, with winds reaching 77.1 km/h.
What is the warmest month in Asso?
The warmest month in Asso is August (25.6 °C on average); the coldest is January (5.3 °C).
How much does it rain in Asso?
Asso receives on average 2,231 mm of precipitation per year, spread over about 161 rainy days.
Is it sunny in Asso?
Asso gets on average 9.0 hours of sunshine per day, roughly 3,285 hours per year over 1940-2025.
What is the biggest single-day snowfall in Asso?
The heaviest 24-hour snowfall measured in Asso between 1940 and 2025 was 10 February 1972, with 11.0 cm.
Are there tropical nights in Asso?
Yes: Asso has on average 89 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Asso?
In Asso, between 1940 and 2025, the highest apparent temperature reached 39.6 °C on 16 July 1994, and the lowest was -12.4 °C on 26 February 1981.
Compare Asso with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Asso