Photo: Quintin Soloviev · CC BY 4.0Mount Vernon has some of the coolest summers among U.S. towns
Midwinter brings lows of about 35°. Winters are mild: January nights here are milder than in 81% of U.S. towns. Compared with 1901–2000, the average now sits 1.3° higher. Seedlings are safe outdoors from about March 27, with the first autumn frost due around November 6.
A year in Mount Vernon at a glance
Each month’s typical high and low, and what it brings.
What stands out about Mount Vernon’s climate
Compared with towns across the U.S., with Mount Vernon’s place in Washington beside it.
What a year in Mount Vernon feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 224 frost-free days a year
In half of years the last 32° night comes by March 27 and the first by November 6. Frost and day counts come from NOAA’s station at Sedro-woolley, WA, 6 miles from the town’s center, at about the same height.
The 2023 USDA map puts Mount Vernon’s center in zone 8b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 16°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
About 6 inches of snow a winter
Snow, measured at Sedro-woolley, WA, falls mostly in December. Precipitation (rain plus melted snow) adds up to 49 inches a year; November is the wettest month and July the driest. Rain or snow falls on about 186 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Mount Vernon
98% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Sedro-woolley, WA.
Living with Mount Vernon’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
224 frost-free days in zone 8b. The last frost comes by Mar 27 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Nov 6.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 29 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Mount Vernon from natural hazards, earthquakes are the largest share (56%); heat waves, cold waves, winter storms and ice storms together are 4%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Mount Vernon and similar climates
TownRatings has no climate map of the towns around Mount Vernon yet.
Climates most like Mount Vernon’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Mount Vernon, WA | 35° | 73° | 49" | 5.7" |
| Fortuna, CA | 42° | 70° | 55" | 0.7" |
| West Haven-Sylvan, OR | 36° | 80° | 44" | 3.6" |
| Nantucket, MA | 26° | 76° | 44" | 25" |
| Boone, NC | 24° | 79° | 58" | 26" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
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°).
A smaller shift than in 53% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Mount Vernon compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Mount Vernon’s place among Washington’s.
Mount Vernon weather by month
Highs, lows and precipitation from NOAA’s grid at Mount Vernon’s center; snow, wet days and snow on the ground from Sedro-woolley, WA. 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" | 0.0" | 17 | 0 | 45° – 54° |
| May | 64° | 46° | 3.4" | 0.0" | 14 | 0 | 51° – 59° |
| June | 68° | 50° | 2.5" | 0.0" | 13 | 0 | 56° – 63° |
| July | 73° | 53° | 1.3" | 0.0" | 7 | 0 | 60° – 67° |
| August | 74° | 53° | 1.5" | 0.0" | 7 | 0 | 60° – 66° |
| September | 69° | 49° | 2.7" | 0.0" | 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 |
How much a month can swing
A normal is an average. January swings the most: from 1991 to 2020 its average ranged from 34° to 47°. September is the most reliable, staying within 5°.
Where Mount Vernon’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Mount Vernon’s center.
- Snow: Sedro-woolley, WA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Sedro-woolley, WA, 6 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Mount Vernon’s climate
What is the weather like in Mount Vernon?
A typical July afternoon reaches 73°, a January night drops to 35°, and about 6 inches of snow falls in a normal winter. Milder January nights than 81% of U.S. towns; cooler July afternoons than all but 145 U.S. towns.
How cold does it get in Mount Vernon in winter?
December nights average 35°. About 46 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 35°.
How much snow does Mount Vernon get?
About 5.7 inches in a normal winter at Sedro-woolley, WA, most of it in December, with snow on the ground about 4 days a year.
How hot does it get in Mount Vernon?
July, with a typical high of 73°. 90° days are rare: none in a normal year at Sedro-woolley, WA.
When is the first and last frost in Mount Vernon?
In half of years the last spring frost (32°) comes by March 27 and the first fall frost by November 6, about 224 frost-free days, at Sedro-woolley, WA.
What growing zone is Mount Vernon in?
Zone 8b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 16°.
What is the best time of year to visit Mount Vernon?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Mount Vernon getting warmer?
Yes: 1991–2020 averaged 1.3° warmer than 1901–2000 on NOAA’s grid. A smaller shift than 53% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Mount Vernon.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.