When to plant in Washington, MO
USDA Zone 6bEverything below — frost dates, hardiness zone, and what to plant when in Washington, Missouri — is derived from the closest NOAA station with complete climate normals.
In zone 6b, Washington gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
WASHINGTON · 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 Washington’s own odds, recorded at WASHINGTON.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 5 | Apr 20 | Apr 7 | Oct 2 | Oct 16 | Oct 27 |
| 32°F | Apr 22 | Apr 8 | Mar 24 | Oct 13 | Oct 25 | Nov 5 |
| 28°F | Apr 11 | Mar 29 | Mar 12 | Oct 22 | Nov 4 | Nov 21 |
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 Washington, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 33 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.
Washington planting FAQ
When is the last spring frost in Washington, MO?
Plan for the last spring frost in Washington around April 8 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.
When is the first fall frost in Washington, MO?
The first fall frost in Washington typically arrives around October 25 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Washington in?
Washington 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 Washington?
Washington has about 200 frost-free days — a moderate growing season — between the average last spring frost (April 8) and first fall frost (October 25).
When should I plant tomatoes in Washington?
For Washington, sow tomatoes indoors about February 11–February 25 and move the seedlings out around April 15, after the last spring frost.
Never miss a window in Washington
An email when it’s time to start seeds, transplant, and sow — timed to Washington’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Union · 13 km
- Wildwood · 30 km
- Wentzville · 32 km
- Lake St. Louis · 32 km
- Eureka · 33 km
- Dardenne Prairie · 33 km
- O'Fallon · 36 km
- Ellisville · 37 km
Frost dates recorded at WASHINGTON, 4 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 Washington, MO — Frost Dates & Zone 6b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00238746. Retrieved from https://blissgarden.com/missouri/washington.