Aki climate — normals and trends
Aki (Japan) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 15.7 °C and it receives 2,411 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 (5.7 °C). Rainfall peaks in June.
Aki averages 8 frost days, 6 hot days (≥ 30 °C) and 156 rainy days per year.
Aki has warmed by +2.1 °C between 1940 and 2025, or +0.25 °C per decade. This trend is statistically significant.
The number of frost days there went from about 15 to 1 per year over the period.
The hottest day of the period reached 34.0 °C (on 30 July 2024) and the coldest -6.1 °C (on 26 February 1981).
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
AkiKochi
- coords
- 33.50°, 133.90°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
15.7°C
Average daily high
18.5°C
Average daily low
13.0°C
Annual rainfall
2,411mm
Sunshine / day
9.0h
Mean relative humidity
73%
Average peak wind
16.4km/h
Seasonal range
19.9°C
Frost days (< 0 °C)
8 d/yr
Hot days (≥ 30 °C)
6 d/yr
Rainy days (≥ 1 mm)
156 d/yr
Annual snowfall
5.4 cm
Average feels-like high
18.6 °C
Average feels-like low
11.9 °C
Average peak gust
38.7 km/h
Tropical nights (≥ 20 °C)
93 d/yr
Solar radiation
15.5 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.1 °C
since 1940
+0.3 °C per decade · r² = 0.68 · 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
34.0 °C
30 July 2024
Coldest day
-6.1 °C
26 February 1981
Wettest day
244 mm
21 August 1970
Windiest day
74.9 km/h
25 September 1964
Strongest gust
176.0 km/h
4 September 1993
Hottest feels-like
39.9 °C
16 August 2024
Coldest feels-like
-12.7 °C
26 February 1981
Snowiest day
18.1 cm
15 February 1968
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 | 9.3 °C | +0.5 °C | 31 mm | -36 mm |
| Feb | 8.1 °C | -1.4 °C | 42 mm | -54 mm |
| Mar | 14.4 °C | +1.6 °C | 168 mm | +9 mm |
| Apr | 18.1 °C | +0.8 °C | 132 mm | -87 mm |
| May | 21.3 °C | +0.5 °C | 379 mm | +133 mm |
| Jun | 25.7 °C | +2.2 °C | 273 mm | -79 mm |
| Jul | 28.7 °C | +1.7 °C | 218 mm | -104 mm |
| Aug | 29.5 °C | +1.5 °C | 166 mm | -118 mm |
| Sep | 28.2 °C | +2.5 °C | 231 mm | -64 mm |
| Oct | 23.6 °C | +2.3 °C | 248 mm | +60 mm |
| Nov | 17.3 °C | +0.9 °C | 50 mm | -68 mm |
| Dec | 12.9 °C | +1.6 °C | 29 mm | -38 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 Aki?
Aki has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 15.7 °C and it receives 2,411 mm of precipitation per year.
What is the hottest day ever recorded in Aki?
The hottest day measured in Aki between 1940 and 2025 was 30 July 2024, reaching 34.0 °C.
What is the coldest day in Aki?
The coldest day measured in Aki between 1940 and 2025 was 26 February 1981, at -6.1 °C.
Does it snow in Aki?
Yes. Aki gets on average 5.4 cm of snow per year and has around 8 frost days.
Has the climate of Aki warmed?
Yes: Aki warmed by +2.1 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Aki?
The wettest day measured in Aki between 1940 and 2025 was 21 August 1970, with 244 mm of rain in 24 hours.
What was the windiest day in Aki?
The windiest day measured in Aki between 1940 and 2025 was 25 September 1964, with winds reaching 74.9 km/h.
What is the warmest month in Aki?
The warmest month in Aki is August (25.6 °C on average); the coldest is January (5.7 °C).
How much does it rain in Aki?
Aki receives on average 2,411 mm of precipitation per year, spread over about 156 rainy days.
Is it sunny in Aki?
Aki 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 Aki?
The heaviest 24-hour snowfall measured in Aki between 1940 and 2025 was 15 February 1968, with 18.1 cm.
Are there tropical nights in Aki?
Yes: Aki has on average 93 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Aki?
In Aki, between 1940 and 2025, the highest apparent temperature reached 39.9 °C on 16 August 2024, and the lowest was -12.7 °C on 26 February 1981.
Compare Aki with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Aki