When to plant in Windsor, CO
USDA Zone 5bEverything below — frost dates, hardiness zone, and what to plant when in Windsor, Colorado — is derived from the closest NOAA station with complete climate normals.
In zone 5b, Windsor gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
FT COLLINS 4 E · 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 Windsor’s own odds, recorded at FT COLLINS 4 E.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 26 | May 14 | May 3 | Sep 13 | Sep 27 | Oct 8 |
| 32°F | May 15 | May 3 | Apr 21 | Sep 22 | Oct 6 | Oct 17 |
| 28°F | May 8 | Apr 23 | Apr 8 | Sep 30 | Oct 14 | Oct 26 |
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 Windsor, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 18 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.
Windsor planting FAQ
When is the last spring frost in Windsor, CO?
On average, the last spring frost in Windsor is around May 3 (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 Windsor, CO?
The first fall frost in Windsor typically arrives around October 6 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Windsor in?
Windsor is in USDA hardiness zone 5b. In zone 5b, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in Windsor?
Windsor has about 156 frost-free days — a moderate growing season — between the average last spring frost (May 3) and first fall frost (October 6).
When should I plant tomatoes in Windsor?
For Windsor, sow tomatoes indoors about March 8–March 22 and move the seedlings out around May 10, after the last spring frost.
Never miss a window in Windsor
An email when it’s time to start seeds, transplant, and sow — timed to Windsor’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Severance · 5 km
- Greeley · 14 km
- Loveland · 14 km
- Fort Collins · 15 km
- Johnstown · 19 km
- Evans · 20 km
- Berthoud · 22 km
- Wellington · 26 km
Frost dates recorded at FT COLLINS 4 E, 14 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 Windsor, CO — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00053006. Retrieved from https://blissgarden.com/colorado/windsor.