Heyan climate — normals and trends
Heyan (China) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 15.9 °C and it receives 1,340 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 (26.1 °C on average) and the coldest is January (4.9 °C). Rainfall peaks in July.
Heyan averages 17 frost days, 45 hot days (≥ 30 °C) and 159 rainy days per year.
Heyan has warmed by +1.0 °C between 1940 and 2025, or +0.11 °C per decade. This trend is statistically significant.
The number of frost days there went from about 23 to 11 per year over the period.
The hottest day of the period reached 39.9 °C (on 24 August 1959) and the coldest -11.6 °C (on 31 January 1969).
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
HeyanChongqing Municipality
- coords
- 31.36°, 108.67°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
15.9°C
Average daily high
19.6°C
Average daily low
12.5°C
Annual rainfall
1,340mm
Sunshine / day
7.0h
Mean relative humidity
77%
Average peak wind
7.1km/h
Seasonal range
21.2°C
Frost days (< 0 °C)
17 d/yr
Hot days (≥ 30 °C)
45 d/yr
Rainy days (≥ 1 mm)
159 d/yr
Annual snowfall
10.4 cm
Average feels-like high
20.3 °C
Average feels-like low
12.4 °C
Average peak gust
23.9 km/h
Tropical nights (≥ 20 °C)
83 d/yr
Solar radiation
12.6 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.0 °C
since 1940
+0.1 °C per decade · r² = 0.29 · 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
39.9 °C
24 August 1959
Coldest day
-11.6 °C
31 January 1969
Wettest day
148 mm
30 June 1991
Windiest day
25.4 km/h
28 May 1946
Strongest gust
68.4 km/h
17 June 1946
Hottest feels-like
44.4 °C
24 July 1961
Coldest feels-like
-16.3 °C
31 January 1969
Snowiest day
10.6 cm
13 January 1957
Sunniest day
13.8 h
8 July 2011
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 | 10.1 °C | +1.9 °C | 47 mm | +7 mm |
| Feb | 9.9 °C | -0.3 °C | 25 mm | -24 mm |
| Mar | 15.3 °C | +0.2 °C | 97 mm | +11 mm |
| Apr | 23.1 °C | +2.9 °C | 63 mm | -41 mm |
| May | 27.0 °C | +3.1 °C | 88 mm | -56 mm |
| Jun | 28.3 °C | +1.3 °C | 150 mm | -12 mm |
| Jul | 34.8 °C | +4.9 °C | 60 mm | -142 mm |
| Aug | 32.9 °C | +2.5 °C | 144 mm | -5 mm |
| Sep | 27.6 °C | +1.9 °C | 185 mm | +20 mm |
| Oct | 21.5 °C | +1.6 °C | 199 mm | +77 mm |
| Nov | 15.4 °C | +0.7 °C | 52 mm | -23 mm |
| Dec | 12.1 °C | +2.5 °C | 45 mm | -0 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 Heyan?
Heyan has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 15.9 °C and it receives 1,340 mm of precipitation per year.
What is the hottest day ever recorded in Heyan?
The hottest day measured in Heyan between 1940 and 2025 was 24 August 1959, reaching 39.9 °C.
What is the coldest day in Heyan?
The coldest day measured in Heyan between 1940 and 2025 was 31 January 1969, at -11.6 °C.
Does it snow in Heyan?
Yes. Heyan gets on average 10.4 cm of snow per year and has around 17 frost days.
Has the climate of Heyan warmed?
Yes: Heyan warmed by +1.0 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Heyan?
The wettest day measured in Heyan between 1940 and 2025 was 30 June 1991, with 148 mm of rain in 24 hours.
What was the windiest day in Heyan?
The windiest day measured in Heyan between 1940 and 2025 was 28 May 1946, with winds reaching 25.4 km/h.
What is the warmest month in Heyan?
The warmest month in Heyan is August (26.1 °C on average); the coldest is January (4.9 °C).
How much does it rain in Heyan?
Heyan receives on average 1,340 mm of precipitation per year, spread over about 159 rainy days.
Is it sunny in Heyan?
Heyan gets on average 7.0 hours of sunshine per day, roughly 2,555 hours per year over 1940-2025.
What is the biggest single-day snowfall in Heyan?
The heaviest 24-hour snowfall measured in Heyan between 1940 and 2025 was 13 January 1957, with 10.6 cm.
Are there tropical nights in Heyan?
Yes: Heyan has on average 83 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Heyan?
In Heyan, between 1940 and 2025, the highest apparent temperature reached 44.4 °C on 24 July 1961, and the lowest was -16.3 °C on 31 January 1969.
Compare Heyan with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Heyan