Mount Vernon climate — normals and trends
Mount Vernon (United States) has a temperate oceanic climate (Cfb) under the Köppen-Geiger classification. Its mean annual temperature is 8.9 °C and it receives 1,942 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 (16.8 °C on average) and the coldest is January (1.9 °C). Rainfall peaks in November.
Mount Vernon averages 56 frost days, 1 hot days (≥ 30 °C) and 173 rainy days per year.
Mount Vernon has warmed by +1.9 °C between 1940 and 2025, or +0.22 °C per decade. This trend is statistically significant.
The number of frost days there went from about 78 to 34 per year over the period.
The hottest day of the period reached 36.3 °C (on 28 June 2021) and the coldest -21.9 °C (on 29 December 1990).
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
Mount VernonWashington
- coords
- 48.42°, -122.33°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
8.9°C
Average daily high
12.4°C
Average daily low
5.7°C
Annual rainfall
1,942mm
Sunshine / day
8.5h
Mean relative humidity
81%
Average peak wind
10.8km/h
Seasonal range
14.9°C
Frost days (< 0 °C)
56 d/yr
Hot days (≥ 30 °C)
1 d/yr
Rainy days (≥ 1 mm)
173 d/yr
Annual snowfall
212.8 cm
Average feels-like high
10.8 °C
Average feels-like low
3.5 °C
Average peak gust
31.6 km/h
Tropical nights (≥ 20 °C)
0 d/yr
Solar radiation
12.5 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.9 °C
since 1940
+0.2 °C per decade · r² = 0.45 · 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
36.3 °C
28 June 2021
Coldest day
-21.9 °C
29 December 1990
Wettest day
95 mm
19 November 1962
Windiest day
36.0 km/h
13 October 1962
Strongest gust
115.9 km/h
13 February 1979
Hottest feels-like
41.4 °C
28 June 2021
Coldest feels-like
-27.3 °C
29 December 1990
Snowiest day
30.0 cm
21 January 1954
Sunniest day
15.8 h
10 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 | 5.5 °C | +1.0 °C | 100 mm | -158 mm |
| Feb | 5.3 °C | -1.0 °C | 172 mm | -32 mm |
| Mar | 9.1 °C | +0.8 °C | 256 mm | +55 mm |
| Apr | 13.3 °C | +2.2 °C | 122 mm | -25 mm |
| May | 15.4 °C | +0.5 °C | 83 mm | -21 mm |
| Jun | 18.4 °C | +0.7 °C | 31 mm | -47 mm |
| Jul | 21.8 °C | +0.8 °C | 7 mm | -34 mm |
| Aug | 22.2 °C | +1.0 °C | 90 mm | +38 mm |
| Sep | 19.8 °C | +1.4 °C | 34 mm | -71 mm |
| Oct | 12.7 °C | -0.3 °C | 222 mm | +16 mm |
| Nov | 9.6 °C | +2.1 °C | 233 mm | -44 mm |
| Dec | 6.8 °C | +2.2 °C | 431 mm | +163 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 Mount Vernon?
Mount Vernon has a temperate oceanic climate (Köppen Cfb). Over 1940-2025, the average annual temperature is 8.9 °C and it receives 1,942 mm of precipitation per year.
What is the hottest day ever recorded in Mount Vernon?
The hottest day measured in Mount Vernon between 1940 and 2025 was 28 June 2021, reaching 36.3 °C.
What is the coldest day in Mount Vernon?
The coldest day measured in Mount Vernon between 1940 and 2025 was 29 December 1990, at -21.9 °C.
Does it snow in Mount Vernon?
Yes. Mount Vernon gets on average 212.8 cm of snow per year and has around 56 frost days.
Has the climate of Mount Vernon warmed?
Yes: Mount Vernon warmed by +1.9 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Mount Vernon?
The wettest day measured in Mount Vernon between 1940 and 2025 was 19 November 1962, with 95 mm of rain in 24 hours.
What was the windiest day in Mount Vernon?
The windiest day measured in Mount Vernon between 1940 and 2025 was 13 October 1962, with winds reaching 36.0 km/h.
What is the warmest month in Mount Vernon?
The warmest month in Mount Vernon is August (16.8 °C on average); the coldest is January (1.9 °C).
How much does it rain in Mount Vernon?
Mount Vernon receives on average 1,942 mm of precipitation per year, spread over about 173 rainy days.
Is it sunny in Mount Vernon?
Mount Vernon gets on average 8.5 hours of sunshine per day, roughly 3,103 hours per year over 1940-2025.
What is the biggest single-day snowfall in Mount Vernon?
The heaviest 24-hour snowfall measured in Mount Vernon between 1940 and 2025 was 21 January 1954, with 30.0 cm.
Are there tropical nights in Mount Vernon?
Almost never: tropical nights (temperature staying above 20 °C) are virtually non-existent in Mount Vernon.
What was the most extreme apparent temperature in Mount Vernon?
In Mount Vernon, between 1940 and 2025, the highest apparent temperature reached 41.4 °C on 28 June 2021, and the lowest was -27.3 °C on 29 December 1990.
Compare Mount Vernon with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Mount Vernon