Iwata climate — normals and trends
Iwata (Japan) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 15.9 °C and it receives 1,992 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 (5.2 °C). Rainfall peaks in June.
Iwata averages 19 frost days, 40 hot days (≥ 30 °C) and 147 rainy days per year.
Iwata has warmed by +2.8 °C between 1940 and 2025, or +0.33 °C per decade. This trend is statistically significant.
The number of frost days there went from about 40 to 0 per year over the period.
The hottest day of the period reached 41.6 °C (on 17 August 2020) and the coldest -6.3 °C (on 18 February 1968).
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
IwataShizuoka
- coords
- 34.70°, 137.85°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
15.9°C
Average daily high
19.9°C
Average daily low
12.4°C
Annual rainfall
1,992mm
Sunshine / day
8.6h
Mean relative humidity
71%
Average peak wind
19.5km/h
Seasonal range
21.9°C
Frost days (< 0 °C)
19 d/yr
Hot days (≥ 30 °C)
40 d/yr
Rainy days (≥ 1 mm)
147 d/yr
Annual snowfall
2.3 cm
Average feels-like high
19.2 °C
Average feels-like low
11.2 °C
Average peak gust
40.1 km/h
Tropical nights (≥ 20 °C)
91 d/yr
Solar radiation
14.7 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.8 °C
since 1940
+0.3 °C per decade · r² = 0.70 · 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
41.6 °C
17 August 2020
Coldest day
-6.3 °C
18 February 1968
Wettest day
219 mm
26 August 1962
Windiest day
81.5 km/h
26 September 1959
Strongest gust
190.1 km/h
26 September 1959
Hottest feels-like
45.9 °C
17 August 2024
Coldest feels-like
-11.0 °C
13 February 1942
Snowiest day
14.2 cm
15 February 1968
Sunniest day
14.0 h
12 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 | 11.1 °C | +1.6 °C | 36 mm | -25 mm |
| Feb | 10.2 °C | -0.3 °C | 30 mm | -53 mm |
| Mar | 15.8 °C | +2.0 °C | 146 mm | +3 mm |
| Apr | 20.5 °C | +1.9 °C | 140 mm | -28 mm |
| May | 23.1 °C | +0.5 °C | 294 mm | +98 mm |
| Jun | 28.2 °C | +2.8 °C | 236 mm | -33 mm |
| Jul | 32.1 °C | +2.9 °C | 189 mm | -68 mm |
| Aug | 33.8 °C | +3.1 °C | 121 mm | -81 mm |
| Sep | 30.5 °C | +3.2 °C | 237 mm | -4 mm |
| Oct | 23.3 °C | +1.1 °C | 208 mm | +17 mm |
| Nov | 17.6 °C | +0.3 °C | 35 mm | -81 mm |
| Dec | 13.3 °C | +1.3 °C | 83 mm | +16 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 Iwata?
Iwata has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 15.9 °C and it receives 1,992 mm of precipitation per year.
What is the hottest day ever recorded in Iwata?
The hottest day measured in Iwata between 1940 and 2025 was 17 August 2020, reaching 41.6 °C.
What is the coldest day in Iwata?
The coldest day measured in Iwata between 1940 and 2025 was 18 February 1968, at -6.3 °C.
Does it snow in Iwata?
Yes. Iwata gets on average 2.3 cm of snow per year and has around 19 frost days.
Has the climate of Iwata warmed?
Yes: Iwata warmed by +2.8 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Iwata?
The wettest day measured in Iwata between 1940 and 2025 was 26 August 1962, with 219 mm of rain in 24 hours.
What was the windiest day in Iwata?
The windiest day measured in Iwata between 1940 and 2025 was 26 September 1959, with winds reaching 81.5 km/h.
What is the warmest month in Iwata?
The warmest month in Iwata is August (27.1 °C on average); the coldest is January (5.2 °C).
How much does it rain in Iwata?
Iwata receives on average 1,992 mm of precipitation per year, spread over about 147 rainy days.
Is it sunny in Iwata?
Iwata gets on average 8.6 hours of sunshine per day, roughly 3,139 hours per year over 1940-2025.
What is the biggest single-day snowfall in Iwata?
The heaviest 24-hour snowfall measured in Iwata between 1940 and 2025 was 15 February 1968, with 14.2 cm.
Are there tropical nights in Iwata?
Yes: Iwata has on average 91 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Iwata?
In Iwata, between 1940 and 2025, the highest apparent temperature reached 45.9 °C on 17 August 2024, and the lowest was -11.0 °C on 13 February 1942.
Compare Iwata with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Iwata