Mount Vernon, WA climate
Mount Vernon has mild winters and cool summers, with plenty of rain. A typical July afternoon reaches 73°, a January night drops to 35°, and about 6 inches of snow falls in a normal winter.
NOAA 1991-2020 climate normals Updated once a decadeWhat a year in Mount Vernon feels like
Winter
Spring
Summer
Fall
Mount Vernon weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 46° | 35° | 6.2" | 0.6" | 20 | 2 | 34° – 47° |
| February | 49° | 35° | 4.3" | 0.2" | 17 | 0 | 35° – 47° |
| March | 53° | 38° | 4.8" | 0.4" | 20 | 0 | 41° – 50° |
| April | 58° | 41° | 4.2" | 0 | 17 | 0 | 45° – 54° |
| May | 64° | 46° | 3.4" | 0 | 14 | 0 | 51° – 59° |
| June | 68° | 50° | 2.5" | 0 | 13 | 0 | 56° – 63° |
| July | 73° | 53° | 1.3" | 0 | 7 | 0 | 60° – 67° |
| August | 74° | 53° | 1.5" | 0 | 7 | 0 | 60° – 66° |
| September | 69° | 49° | 2.7" | 0 | 12 | 0 | 57° – 62° |
| October | 59° | 44° | 5.0" | 0.1" | 18 | 0 | 48° – 56° |
| November | 51° | 39° | 7.0" | 0.7" | 21 | 1 | 40° – 50° |
| December | 45° | 35° | 6.0" | 3.7" | 21 | 1 | 35° – 43° |
| Year | 59° | 43° | 49.0" | 5.7" | 186 | 4 |
“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.
Rain and snow in Mount Vernon
Mount Vernon gets 49 inches of rain and melted snow a year. November is the wettest month and July the driest. Rain or snow falls on about 186 days a year.
About 224 frost-free days a year
In half of years the last 32° night comes by March 24 and the first one by November 3. That leaves about 224 frost-free days for gardens, longer than 84% of U.S. towns.
Heating and cooling a home in Mount Vernon
Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Mount Vernon, 99% of that work is heating and 1% is cooling, so the furnace matters far more than the air conditioner.
Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.
How Mount Vernon compares
Compared with every U.S. town and city on TownTapestry, each counted once.
Warmer than it used to be
The last 30 years in Mount Vernon averaged 1.3° warmer than the 1900s. The biggest change is in January (+3.2°). The shift is larger than in 59% of U.S. towns.
Change by month1991–2020 average minus 1901–2000 average, at Mount Vernon’s spot on NOAA’s grid
How much a month can swing
A normal is an average, and real years wander around it. January swings the most: between 1991 and 2020 its average temperature ranged from 34° to 47°. September is the most reliable, staying within 5°.
Common questions about Mount Vernon’s climate
What is the coldest month in Mount Vernon?
December, with a typical high of 45° and a low of 35°.
What is the hottest month in Mount Vernon?
August, with a typical high of 74° and a low of 53°.
How much snow does Mount Vernon get?
About 6 inches in a normal winter, most of it in December.
When is the first frost in Mount Vernon?
In half of years the first 32° night comes by November 3, and the last spring frost by March 24.
What is the rainiest month in Mount Vernon?
November, with 7.0 inches of rain and melted snow. The year totals 49 inches.
Temperatures and rainfall come from NOAA’s gridded climate normals for Mount Vernon itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Sedro-woolley, WA (6 mi, snow) and Mt Vernon 3 Wnw, WA (4 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.