Ina climate — normals and trends
Ina (Japan) has a warm-summer humid continental climate (Dfb) under the Köppen-Geiger classification. Its mean annual temperature is 8.8 °C and it receives 1,622 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 (21.4 °C on average) and the coldest is January (-5.0 °C). Rainfall peaks in July.
Ina averages 132 frost days, 2 hot days (≥ 30 °C) and 155 rainy days per year.
Ina has warmed by +3.4 °C between 1940 and 2025, or +0.40 °C per decade. This trend is statistically significant.
The number of frost days there went from about 149 to 115 per year over the period.
The hottest day of the period reached 33.4 °C (on 6 August 2018) and the coldest -27.2 °C (on 4 January 1958).
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
InaNagano
- coords
- 35.83°, 137.95°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
8.8°C
Average daily high
13.7°C
Average daily low
4.3°C
Annual rainfall
1,622mm
Sunshine / day
8.7h
Mean relative humidity
73%
Average peak wind
9.2km/h
Seasonal range
26.4°C
Frost days (< 0 °C)
132 d/yr
Hot days (≥ 30 °C)
2 d/yr
Rainy days (≥ 1 mm)
155 d/yr
Annual snowfall
146.6 cm
Average feels-like high
12.4 °C
Average feels-like low
2.5 °C
Average peak gust
37.8 km/h
Tropical nights (≥ 20 °C)
4 d/yr
Solar radiation
15.0 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+3.4 °C
since 1940
+0.4 °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
33.4 °C
6 August 2018
Coldest day
-27.2 °C
4 January 1958
Wettest day
170 mm
5 October 1945
Windiest day
37.3 km/h
27 September 1959
Strongest gust
205.2 km/h
26 September 1959
Hottest feels-like
37.3 °C
3 August 2024
Coldest feels-like
-32.1 °C
1 February 1941
Snowiest day
37.4 cm
15 February 2014
Sunniest day
14.0 h
9 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 | 2.6 °C | +1.9 °C | 50 mm | -24 mm |
| Feb | 1.4 °C | -0.5 °C | 59 mm | -27 mm |
| Mar | 8.6 °C | +2.5 °C | 156 mm | +27 mm |
| Apr | 15.1 °C | +2.0 °C | 94 mm | -41 mm |
| May | 19.3 °C | +1.3 °C | 162 mm | +16 mm |
| Jun | 24.1 °C | +3.0 °C | 173 mm | -33 mm |
| Jul | 28.5 °C | +3.7 °C | 125 mm | -86 mm |
| Aug | 28.6 °C | +2.6 °C | 95 mm | -46 mm |
| Sep | 25.1 °C | +2.9 °C | 195 mm | +19 mm |
| Oct | 17.4 °C | +1.1 °C | 151 mm | -1 mm |
| Nov | 10.6 °C | +0.1 °C | 44 mm | -51 mm |
| Dec | 5.7 °C | +1.7 °C | 79 mm | +6 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 Ina?
Ina has a warm-summer humid continental climate (Köppen Dfb). Over 1940-2025, the average annual temperature is 8.8 °C and it receives 1,622 mm of precipitation per year.
What is the hottest day ever recorded in Ina?
The hottest day measured in Ina between 1940 and 2025 was 6 August 2018, reaching 33.4 °C.
What is the coldest day in Ina?
The coldest day measured in Ina between 1940 and 2025 was 4 January 1958, at -27.2 °C.
Does it snow in Ina?
Yes. Ina gets on average 146.6 cm of snow per year and has around 132 frost days.
Has the climate of Ina warmed?
Yes: Ina warmed by +3.4 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Ina?
The wettest day measured in Ina between 1940 and 2025 was 5 October 1945, with 170 mm of rain in 24 hours.
What was the windiest day in Ina?
The windiest day measured in Ina between 1940 and 2025 was 27 September 1959, with winds reaching 37.3 km/h.
What is the warmest month in Ina?
The warmest month in Ina is August (21.4 °C on average); the coldest is January (-5.0 °C).
How much does it rain in Ina?
Ina receives on average 1,622 mm of precipitation per year, spread over about 155 rainy days.
Is it sunny in Ina?
Ina 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 Ina?
The heaviest 24-hour snowfall measured in Ina between 1940 and 2025 was 15 February 2014, with 37.4 cm.
Are there tropical nights in Ina?
Yes: Ina has on average 4 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Ina?
In Ina, between 1940 and 2025, the highest apparent temperature reached 37.3 °C on 3 August 2024, and the lowest was -32.1 °C on 1 February 1941.
Compare Ina with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Ina