When to plant in Mount Vernon, IL
USDA Zone 6bEverything below — frost dates, hardiness zone, and what to plant when in Mount Vernon, Illinois — is derived from the closest NOAA station with complete climate normals.
Zone 6b means Mount Vernon sees real winter cold, but a good range of perennials survive; the frost dates above govern when annual vegetables go out.
Frost probability
MT VERNON 3 NE · 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 NE.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 8 | Apr 23 | Apr 9 | Sep 30 | Oct 12 | Oct 25 |
| 32°F | Apr 26 | Apr 11 | Mar 30 | Oct 9 | Oct 22 | Nov 1 |
| 28°F | Apr 17 | Apr 1 | Mar 16 | Oct 20 | Nov 1 | Nov 16 |
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 31 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, IL?
On average, the last spring frost in Mount Vernon is around April 11 (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, IL?
Expect Mount Vernon's first fall frost near October 22 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Mount Vernon in?
Mount Vernon is in USDA hardiness zone 6b. In zone 6b, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Mount Vernon?
There are roughly 194 frost-free days in Mount Vernon (a moderate growing season), running from the average last frost around April 11 to the first fall frost near October 22.
When should I plant tomatoes in Mount Vernon?
In Mount Vernon, start tomato seeds indoors around February 14–February 28, then transplant seedlings outdoors around April 18 once the danger of frost has passed.
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 reachFrost dates recorded at MT VERNON 3 NE, 7 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, IL — Frost Dates & Zone 6b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00115943. Retrieved from https://blissgarden.com/illinois/mount-vernon.