Inzai climate — normals and trends
Inzai (Japan) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 15.4 °C and it receives 1,426 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 (26.6 °C on average) and the coldest is January (4.6 °C). Rainfall peaks in October.
Inzai averages 21 frost days, 35 hot days (≥ 30 °C) and 143 rainy days per year.
Inzai has warmed by +2.0 °C between 1940 and 2025, or +0.23 °C per decade. This trend is statistically significant.
The number of frost days there went from about 37 to 5 per year over the period.
The hottest day of the period reached 38.0 °C (on 3 August 1994) and the coldest -9.6 °C (on 5 February 1952).
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
InzaiChiba
- coords
- 35.83°, 140.16°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
15.4°C
Average daily high
19.0°C
Average daily low
12.3°C
Annual rainfall
1,426mm
Sunshine / day
8.3h
Mean relative humidity
75%
Average peak wind
18.0km/h
Seasonal range
22.0°C
Frost days (< 0 °C)
21 d/yr
Hot days (≥ 30 °C)
35 d/yr
Rainy days (≥ 1 mm)
143 d/yr
Annual snowfall
9.0 cm
Average feels-like high
18.6 °C
Average feels-like low
11.2 °C
Average peak gust
34.7 km/h
Tropical nights (≥ 20 °C)
84 d/yr
Solar radiation
14.1 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.0 °C
since 1940
+0.2 °C per decade · r² = 0.60 · 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
38.0 °C
3 August 1994
Coldest day
-9.6 °C
5 February 1952
Wettest day
197 mm
26 September 1958
Windiest day
71.7 km/h
5 December 2004
Strongest gust
141.1 km/h
1 October 2018
Hottest feels-like
44.9 °C
16 August 2007
Coldest feels-like
-14.9 °C
5 February 1952
Snowiest day
22.9 cm
8 February 2014
Sunniest day
14.0 h
20 June 1962
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 | 10.4 °C | +1.8 °C | 43 mm | -16 mm |
| Feb | 10.2 °C | +1.0 °C | 14 mm | -56 mm |
| Mar | 14.7 °C | +2.2 °C | 163 mm | +50 mm |
| Apr | 19.2 °C | +1.6 °C | 127 mm | +12 mm |
| May | 22.1 °C | +0.2 °C | 181 mm | +52 mm |
| Jun | 27.9 °C | +3.2 °C | 130 mm | -29 mm |
| Jul | 31.6 °C | +3.1 °C | 68 mm | -72 mm |
| Aug | 33.0 °C | +2.9 °C | 51 mm | -71 mm |
| Sep | 29.8 °C | +3.5 °C | 142 mm | -28 mm |
| Oct | 21.3 °C | +0.4 °C | 144 mm | -44 mm |
| Nov | 16.4 °C | +0.4 °C | 55 mm | -45 mm |
| Dec | 12.1 °C | +1.0 °C | 77 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 Inzai?
Inzai has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 15.4 °C and it receives 1,426 mm of precipitation per year.
What is the hottest day ever recorded in Inzai?
The hottest day measured in Inzai between 1940 and 2025 was 3 August 1994, reaching 38.0 °C.
What is the coldest day in Inzai?
The coldest day measured in Inzai between 1940 and 2025 was 5 February 1952, at -9.6 °C.
Does it snow in Inzai?
Yes. Inzai gets on average 9.0 cm of snow per year and has around 21 frost days.
Has the climate of Inzai warmed?
Yes: Inzai warmed by +2.0 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Inzai?
The wettest day measured in Inzai between 1940 and 2025 was 26 September 1958, with 197 mm of rain in 24 hours.
What was the windiest day in Inzai?
The windiest day measured in Inzai between 1940 and 2025 was 5 December 2004, with winds reaching 71.7 km/h.
What is the warmest month in Inzai?
The warmest month in Inzai is August (26.6 °C on average); the coldest is January (4.6 °C).
How much does it rain in Inzai?
Inzai receives on average 1,426 mm of precipitation per year, spread over about 143 rainy days.
Is it sunny in Inzai?
Inzai gets on average 8.3 hours of sunshine per day, roughly 3,030 hours per year over 1940-2025.
What is the biggest single-day snowfall in Inzai?
The heaviest 24-hour snowfall measured in Inzai between 1940 and 2025 was 8 February 2014, with 22.9 cm.
Are there tropical nights in Inzai?
Yes: Inzai has on average 84 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Inzai?
In Inzai, between 1940 and 2025, the highest apparent temperature reached 44.9 °C on 16 August 2007, and the lowest was -14.9 °C on 5 February 1952.
Compare Inzai with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Inzai