When to plant in Troy, MO
USDA Zone 6bEverything below — frost dates, hardiness zone, and what to plant when in Troy, Missouri — is derived from the closest NOAA station with complete climate normals.
Troy's nearest full-normals station sits about 21 km out, so treat these as a close estimate — local microclimate can nudge your first and last frost. In zone 6b, Troy gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
WARRENTON 1 N · 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 Troy’s own odds, recorded at WARRENTON 1 N.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 14 | Apr 28 | Apr 11 | Sep 29 | Oct 14 | Oct 25 |
| 32°F | May 3 | Apr 14 | Mar 31 | Oct 9 | Oct 23 | Nov 5 |
| 28°F | Apr 18 | Apr 3 | Mar 17 | Oct 20 | Nov 2 | Nov 18 |
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 Troy, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 39 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.
Troy planting FAQ
When is the last spring frost in Troy, MO?
Plan for the last spring frost in Troy around April 14 (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 Troy, MO?
The first fall frost in Troy typically arrives around October 23 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Troy in?
Troy 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 Troy?
Troy has about 192 frost-free days — a moderate growing season — between the average last spring frost (April 14) and first fall frost (October 23).
When should I plant tomatoes in Troy?
For Troy, sow tomatoes indoors about February 17–March 3 and move the seedlings out around April 21, after the last spring frost.
Never miss a window in Troy
An email when it’s time to start seeds, transplant, and sow — timed to Troy’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Wentzville · 19 km
- Lake St. Louis · 26 km
- O'Fallon · 30 km
- Dardenne Prairie · 34 km
- St. Peters · 38 km
- St. Charles · 44 km
- Washington · 47 km
- Chesterfield · 49 km
Frost dates recorded at WARRENTON 1 N, 21 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 Troy, MO — Frost Dates & Zone 6b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00238725. Retrieved from https://blissgarden.com/missouri/troy.