Southbury climate — normals and trends
Southbury (United States) has a hot-summer humid continental climate (Dfa) under the Köppen-Geiger classification. Its mean annual temperature is 10.2 °C and it receives 1,183 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 July (22.7 °C on average) and the coldest is January (-2.4 °C). Rainfall peaks in August.
Southbury averages 104 frost days, 18 hot days (≥ 30 °C) and 125 rainy days per year.
Southbury has warmed by +1.8 °C between 1940 and 2025, or +0.21 °C per decade. This trend is statistically significant.
The number of frost days there went from about 114 to 94 per year over the period.
The hottest day of the period reached 39.2 °C (on 3 July 1966) and the coldest -24.7 °C (on 12 January 1981).
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
SouthburyConnecticut
- coords
- 41.48°, -73.21°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
10.2°C
Average daily high
14.8°C
Average daily low
6.0°C
Annual rainfall
1,183mm
Sunshine / day
8.8h
Mean relative humidity
69%
Average peak wind
16.9km/h
Seasonal range
25.1°C
Frost days (< 0 °C)
104 d/yr
Hot days (≥ 30 °C)
18 d/yr
Rainy days (≥ 1 mm)
125 d/yr
Annual snowfall
91.7 cm
Average feels-like high
13.0 °C
Average feels-like low
3.2 °C
Average peak gust
41.1 km/h
Tropical nights (≥ 20 °C)
21 d/yr
Solar radiation
14.6 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.8 °C
since 1940
+0.2 °C per decade · r² = 0.42 · 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
39.2 °C
3 July 1966
Coldest day
-24.7 °C
12 January 1981
Wettest day
151 mm
14 September 1944
Windiest day
55.3 km/h
25 November 1950
Strongest gust
145.8 km/h
25 November 1950
Hottest feels-like
43.4 °C
26 August 1948
Coldest feels-like
-30.3 °C
12 January 1981
Snowiest day
33.0 cm
14 March 2017
Sunniest day
14.4 h
12 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 | 0.8 °C | -0.6 °C | 38 mm | -51 mm |
| Feb | 2.5 °C | -0.3 °C | 83 mm | +0 mm |
| Mar | 11.2 °C | +3.6 °C | 111 mm | +8 mm |
| Apr | 15.5 °C | +1.5 °C | 87 mm | -13 mm |
| May | 19.1 °C | -0.6 °C | 217 mm | +113 mm |
| Jun | 25.4 °C | +0.7 °C | 66 mm | -32 mm |
| Jul | 28.8 °C | +1.2 °C | 118 mm | +15 mm |
| Aug | 26.6 °C | +0.1 °C | 40 mm | -71 mm |
| Sep | 24.1 °C | +1.6 °C | 93 mm | -4 mm |
| Oct | 16.9 °C | +0.3 °C | 150 mm | +53 mm |
| Nov | 9.7 °C | -0.4 °C | 58 mm | -40 mm |
| Dec | 2.4 °C | -1.5 °C | 80 mm | -21 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 Southbury?
Southbury has a hot-summer humid continental climate (Köppen Dfa). Over 1940-2025, the average annual temperature is 10.2 °C and it receives 1,183 mm of precipitation per year.
What is the hottest day ever recorded in Southbury?
The hottest day measured in Southbury between 1940 and 2025 was 3 July 1966, reaching 39.2 °C.
What is the coldest day in Southbury?
The coldest day measured in Southbury between 1940 and 2025 was 12 January 1981, at -24.7 °C.
Does it snow in Southbury?
Yes. Southbury gets on average 91.7 cm of snow per year and has around 104 frost days.
Has the climate of Southbury warmed?
Yes: Southbury warmed by +1.8 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Southbury?
The wettest day measured in Southbury between 1940 and 2025 was 14 September 1944, with 151 mm of rain in 24 hours.
What was the windiest day in Southbury?
The windiest day measured in Southbury between 1940 and 2025 was 25 November 1950, with winds reaching 55.3 km/h.
What is the warmest month in Southbury?
The warmest month in Southbury is July (22.7 °C on average); the coldest is January (-2.4 °C).
How much does it rain in Southbury?
Southbury receives on average 1,183 mm of precipitation per year, spread over about 125 rainy days.
Is it sunny in Southbury?
Southbury gets on average 8.8 hours of sunshine per day, roughly 3,212 hours per year over 1940-2025.
What is the biggest single-day snowfall in Southbury?
The heaviest 24-hour snowfall measured in Southbury between 1940 and 2025 was 14 March 2017, with 33.0 cm.
Are there tropical nights in Southbury?
Yes: Southbury has on average 21 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Southbury?
In Southbury, between 1940 and 2025, the highest apparent temperature reached 43.4 °C on 26 August 1948, and the lowest was -30.3 °C on 12 January 1981.
Compare Southbury with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Southbury