Karatsu climate — normals and trends
Karatsu (Japan) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 16.5 °C and it receives 1,696 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 (27.1 °C on average) and the coldest is January (6.8 °C). Rainfall peaks in June.
Karatsu averages 1 frost days, 17 hot days (≥ 30 °C) and 150 rainy days per year.
Karatsu has warmed by +1.9 °C between 1940 and 2025, or +0.22 °C per decade. This trend is statistically significant.
The number of frost days there went from about 2 to 0 per year over the period.
The hottest day of the period reached 33.8 °C (on 10 August 1994) and the coldest -3.5 °C (on 16 February 1977).
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
KaratsuSaga
- coords
- 33.44°, 129.97°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
16.5°C
Average daily high
18.7°C
Average daily low
14.5°C
Annual rainfall
1,696mm
Sunshine / day
8.2h
Mean relative humidity
75%
Average peak wind
19.7km/h
Seasonal range
20.3°C
Frost days (< 0 °C)
1 d/yr
Hot days (≥ 30 °C)
17 d/yr
Rainy days (≥ 1 mm)
150 d/yr
Annual snowfall
8.5 cm
Average feels-like high
18.5 °C
Average feels-like low
13.4 °C
Average peak gust
37.2 km/h
Tropical nights (≥ 20 °C)
106 d/yr
Solar radiation
14.1 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.9 °C
since 1940
+0.2 °C per decade · r² = 0.64 · 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 1994
Coldest day
-3.5 °C
16 February 1977
Wettest day
181 mm
24 June 2012
Windiest day
70.9 km/h
27 September 1991
Strongest gust
183.6 km/h
31 August 1987
Hottest feels-like
41.5 °C
25 July 2024
Coldest feels-like
-12.0 °C
16 February 1977
Snowiest day
17.9 cm
15 February 1968
Sunniest day
13.7 h
13 June 2004
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 | 9.2 °C | +0.5 °C | 33 mm | -45 mm |
| Feb | 7.5 °C | -1.8 °C | 62 mm | -22 mm |
| Mar | 13.2 °C | +0.8 °C | 141 mm | +29 mm |
| Apr | 17.4 °C | +0.6 °C | 66 mm | -72 mm |
| May | 20.6 °C | -0.2 °C | 226 mm | +73 mm |
| Jun | 25.1 °C | +1.3 °C | 357 mm | +89 mm |
| Jul | 30.4 °C | +2.7 °C | 112 mm | -143 mm |
| Aug | 30.5 °C | +1.3 °C | 285 mm | +119 mm |
| Sep | 28.9 °C | +2.9 °C | 179 mm | -0 mm |
| Oct | 24.0 °C | +2.7 °C | 52 mm | -47 mm |
| Nov | 17.5 °C | +1.0 °C | 36 mm | -53 mm |
| Dec | 13.1 °C | +1.8 °C | 63 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 Karatsu?
Karatsu has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 16.5 °C and it receives 1,696 mm of precipitation per year.
What is the hottest day ever recorded in Karatsu?
The hottest day measured in Karatsu between 1940 and 2025 was 10 August 1994, reaching 33.8 °C.
What is the coldest day in Karatsu?
The coldest day measured in Karatsu between 1940 and 2025 was 16 February 1977, at -3.5 °C.
Does it snow in Karatsu?
Yes. Karatsu gets on average 8.5 cm of snow per year and has around 1 frost days.
Has the climate of Karatsu warmed?
Yes: Karatsu warmed by +1.9 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Karatsu?
The wettest day measured in Karatsu between 1940 and 2025 was 24 June 2012, with 181 mm of rain in 24 hours.
What was the windiest day in Karatsu?
The windiest day measured in Karatsu between 1940 and 2025 was 27 September 1991, with winds reaching 70.9 km/h.
What is the warmest month in Karatsu?
The warmest month in Karatsu is August (27.1 °C on average); the coldest is January (6.8 °C).
How much does it rain in Karatsu?
Karatsu receives on average 1,696 mm of precipitation per year, spread over about 150 rainy days.
Is it sunny in Karatsu?
Karatsu gets on average 8.2 hours of sunshine per day, roughly 2,993 hours per year over 1940-2025.
What is the biggest single-day snowfall in Karatsu?
The heaviest 24-hour snowfall measured in Karatsu between 1940 and 2025 was 15 February 1968, with 17.9 cm.
Are there tropical nights in Karatsu?
Yes: Karatsu has on average 106 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Karatsu?
In Karatsu, between 1940 and 2025, the highest apparent temperature reached 41.5 °C on 25 July 2024, and the lowest was -12.0 °C on 16 February 1977.
Compare Karatsu with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Karatsu