When to plant in Mount Vernon, WA
USDA Zone 8bMount Vernon, Washington frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
In zone 8b, Mount Vernon supports a wide range of perennials year-round; the frost dates above are what set your annual vegetable timing.
The average first fall frost in Mount Vernon is now 7 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
MT VERNON 3 WNW · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Mount Vernon’s own odds, recorded at MT VERNON 3 WNW.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 5 | Apr 18 | Mar 29 | Sep 29 | Oct 16 | Nov 6 |
| 32°F | Apr 14 | Mar 24 | Mar 3 | Oct 12 | Nov 3 | Nov 25 |
| 28°F | Mar 17 | Feb 27 | Jan 23 | Oct 31 | Nov 25 | Dec 23 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Mount Vernon, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 25 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Mount Vernon planting FAQ
When is the last spring frost in Mount Vernon, WA?
On average, the last spring frost in Mount Vernon is around March 24 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in Mount Vernon, WA?
In Mount Vernon, the first 32°F freeze of fall lands around November 3 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Mount Vernon in?
Mount Vernon is in USDA hardiness zone 8b. In zone 8b, winters are mild — many tender perennials overwinter here.
How long is the growing season in Mount Vernon?
Mount Vernon has about 224 frost-free days — a long growing season — between the average last spring frost (March 24) and first fall frost (November 3).
When should I plant tomatoes in Mount Vernon?
For Mount Vernon, sow tomatoes indoors about January 27–February 10 and move the seedlings out around March 31, after the last spring frost.
Never miss a window in Mount Vernon
An email when it’s time to start seeds, transplant, and sow — timed to Mount Vernon’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Burlington · 6 km
- Sedro-Woolley · 12 km
- Anacortes · 24 km
- Oak Harbor · 27 km
- Arlington · 30 km
- Camano · 31 km
- Bellingham · 39 km
- Marysville · 39 km
Frost dates recorded at MT VERNON 3 WNW, 6 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Mount Vernon, WA — Frost Dates & Zone 8b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00455678. Retrieved from https://blissgarden.com/washington/mount-vernon.