Delaware climate — normals and trends
Delaware (United States) has a hot-summer humid continental climate (Dfa) under the Köppen-Geiger classification. Its mean annual temperature is 10.8 °C and it receives 1,036 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 (23.0 °C on average) and the coldest is January (-2.6 °C). Rainfall peaks in May.
Delaware averages 107 frost days, 23 hot days (≥ 30 °C) and 131 rainy days per year.
Delaware 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 119 to 95 per year over the period.
The hottest day of the period reached 38.2 °C (on 16 July 1988) and the coldest -31.1 °C (on 19 January 1994).
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
DelawareOhio
- coords
- 40.30°, -83.07°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
10.8°C
Average daily high
15.7°C
Average daily low
6.1°C
Annual rainfall
1,036mm
Sunshine / day
8.6h
Mean relative humidity
71%
Average peak wind
18.6km/h
Seasonal range
25.6°C
Frost days (< 0 °C)
107 d/yr
Hot days (≥ 30 °C)
23 d/yr
Rainy days (≥ 1 mm)
131 d/yr
Annual snowfall
61.6 cm
Average feels-like high
13.8 °C
Average feels-like low
3.5 °C
Average peak gust
37.8 km/h
Tropical nights (≥ 20 °C)
26 d/yr
Solar radiation
14.7 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.8 °C
since 1940
+0.2 °C per decade · r² = 0.36 · 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
38.2 °C
16 July 1988
Coldest day
-31.1 °C
19 January 1994
Wettest day
100 mm
14 September 1979
Windiest day
51.3 km/h
25 March 1947
Strongest gust
109.1 km/h
25 March 1947
Hottest feels-like
42.0 °C
22 July 2011
Coldest feels-like
-36.8 °C
19 January 1994
Snowiest day
23.5 cm
22 March 1968
Sunniest day
14.9 h
18 June 1941
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 | -1.2 °C | -2.6 °C | 39 mm | -41 mm |
| Feb | 3.3 °C | 0.0 °C | 104 mm | +31 mm |
| Mar | 14.2 °C | +5.1 °C | 95 mm | -6 mm |
| Apr | 17.6 °C | +1.7 °C | 153 mm | +48 mm |
| May | 19.9 °C | -1.6 °C | 169 mm | +61 mm |
| Jun | 27.5 °C | +1.4 °C | 149 mm | +52 mm |
| Jul | 28.9 °C | +0.9 °C | 130 mm | +38 mm |
| Aug | 26.3 °C | -1.0 °C | 24 mm | -51 mm |
| Sep | 26.2 °C | +2.3 °C | 48 mm | -21 mm |
| Oct | 18.6 °C | +1.1 °C | 95 mm | +27 mm |
| Nov | 9.8 °C | -0.2 °C | 49 mm | -36 mm |
| Dec | 3.6 °C | -0.2 °C | 71 mm | -12 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 Delaware?
Delaware has a hot-summer humid continental climate (Köppen Dfa). Over 1940-2025, the average annual temperature is 10.8 °C and it receives 1,036 mm of precipitation per year.
What is the hottest day ever recorded in Delaware?
The hottest day measured in Delaware between 1940 and 2025 was 16 July 1988, reaching 38.2 °C.
What is the coldest day in Delaware?
The coldest day measured in Delaware between 1940 and 2025 was 19 January 1994, at -31.1 °C.
Does it snow in Delaware?
Yes. Delaware gets on average 61.6 cm of snow per year and has around 107 frost days.
Has the climate of Delaware warmed?
Yes: Delaware warmed by +1.8 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Delaware?
The wettest day measured in Delaware between 1940 and 2025 was 14 September 1979, with 100 mm of rain in 24 hours.
What was the windiest day in Delaware?
The windiest day measured in Delaware between 1940 and 2025 was 25 March 1947, with winds reaching 51.3 km/h.
What is the warmest month in Delaware?
The warmest month in Delaware is July (23.0 °C on average); the coldest is January (-2.6 °C).
How much does it rain in Delaware?
Delaware receives on average 1,036 mm of precipitation per year, spread over about 131 rainy days.
Is it sunny in Delaware?
Delaware gets on average 8.6 hours of sunshine per day, roughly 3,139 hours per year over 1940-2025.
What is the biggest single-day snowfall in Delaware?
The heaviest 24-hour snowfall measured in Delaware between 1940 and 2025 was 22 March 1968, with 23.5 cm.
Are there tropical nights in Delaware?
Yes: Delaware has on average 26 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Delaware?
In Delaware, between 1940 and 2025, the highest apparent temperature reached 42.0 °C on 22 July 2011, and the lowest was -36.8 °C on 19 January 1994.
Compare Delaware with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Delaware