Decatur climate — normals and trends
Decatur (United States) has a humid subtropical climate (Cfa) under the Köppen-Geiger classification. Its mean annual temperature is 16.3 °C and it receives 1,258 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 (26.4 °C on average) and the coldest is January (5.1 °C). Rainfall peaks in March.
Decatur averages 41 frost days, 73 hot days (≥ 30 °C) and 123 rainy days per year.
Decatur has warmed by +1.3 °C between 1940 and 2025, or +0.15 °C per decade. This trend is statistically significant.
The number of frost days there went from about 46 to 36 per year over the period.
The hottest day of the period reached 39.9 °C (on 27 July 1952) and the coldest -26.4 °C (on 21 January 1985).
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
DecaturAlabama
- coords
- 34.61°, -86.98°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
16.3°C
Average daily high
21.4°C
Average daily low
11.7°C
Annual rainfall
1,258mm
Sunshine / day
9.2h
Mean relative humidity
71%
Average peak wind
14.6km/h
Seasonal range
21.3°C
Frost days (< 0 °C)
41 d/yr
Hot days (≥ 30 °C)
73 d/yr
Rainy days (≥ 1 mm)
123 d/yr
Annual snowfall
8.2 cm
Average feels-like high
21.4 °C
Average feels-like low
10.7 °C
Average peak gust
33.6 km/h
Tropical nights (≥ 20 °C)
91 d/yr
Solar radiation
16.1 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.3 °C
since 1940
+0.2 °C per decade · r² = 0.26 · 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
27 July 1952
Coldest day
-26.4 °C
21 January 1985
Wettest day
188 mm
5 September 2011
Windiest day
47.2 km/h
30 August 2005
Strongest gust
122.8 km/h
30 August 2005
Hottest feels-like
43.8 °C
15 July 1980
Coldest feels-like
-31.9 °C
21 January 1985
Snowiest day
18.7 cm
23 January 1940
Sunniest day
14.0 h
20 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 | 8.6 °C | -1.1 °C | 92 mm | -32 mm |
| Feb | 15.2 °C | +3.0 °C | 115 mm | -8 mm |
| Mar | 20.1 °C | +3.4 °C | 145 mm | -1 mm |
| Apr | 24.2 °C | +2.4 °C | 140 mm | +17 mm |
| May | 25.3 °C | -0.7 °C | 209 mm | +108 mm |
| Jun | 30.1 °C | +0.2 °C | 140 mm | +55 mm |
| Jul | 32.3 °C | +1.1 °C | 50 mm | -49 mm |
| Aug | 30.3 °C | -0.6 °C | 54 mm | -22 mm |
| Sep | 29.8 °C | +1.9 °C | 48 mm | -41 mm |
| Oct | 23.4 °C | +0.9 °C | 104 mm | +30 mm |
| Nov | 18.2 °C | +2.1 °C | 60 mm | -41 mm |
| Dec | 12.9 °C | +1.5 °C | 54 mm | -65 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 Decatur?
Decatur has a humid subtropical climate (Köppen Cfa). Over 1940-2025, the average annual temperature is 16.3 °C and it receives 1,258 mm of precipitation per year.
What is the hottest day ever recorded in Decatur?
The hottest day measured in Decatur between 1940 and 2025 was 27 July 1952, reaching 39.9 °C.
What is the coldest day in Decatur?
The coldest day measured in Decatur between 1940 and 2025 was 21 January 1985, at -26.4 °C.
Does it snow in Decatur?
Yes. Decatur gets on average 8.2 cm of snow per year and has around 41 frost days.
Has the climate of Decatur warmed?
Yes: Decatur warmed by +1.3 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Decatur?
The wettest day measured in Decatur between 1940 and 2025 was 5 September 2011, with 188 mm of rain in 24 hours.
What was the windiest day in Decatur?
The windiest day measured in Decatur between 1940 and 2025 was 30 August 2005, with winds reaching 47.2 km/h.
What is the warmest month in Decatur?
The warmest month in Decatur is July (26.4 °C on average); the coldest is January (5.1 °C).
How much does it rain in Decatur?
Decatur receives on average 1,258 mm of precipitation per year, spread over about 123 rainy days.
Is it sunny in Decatur?
Decatur gets on average 9.2 hours of sunshine per day, roughly 3,358 hours per year over 1940-2025.
What is the biggest single-day snowfall in Decatur?
The heaviest 24-hour snowfall measured in Decatur between 1940 and 2025 was 23 January 1940, with 18.7 cm.
Are there tropical nights in Decatur?
Yes: Decatur has on average 91 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Decatur?
In Decatur, between 1940 and 2025, the highest apparent temperature reached 43.8 °C on 15 July 1980, and the lowest was -31.9 °C on 21 January 1985.
Compare Decatur with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Decatur