When to plant in Monument, CO
USDA Zone 5bHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Monument, Colorado — all computed from Monument's nearest NOAA weather station.
In zone 5b, Monument gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
MONUMENT 3S · 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 Monument’s own odds, recorded at MONUMENT 3S.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Jun 12 | May 29 | May 16 | Sep 9 | Sep 23 | Oct 2 |
| 32°F | May 30 | May 17 | May 5 | Sep 19 | Oct 1 | Oct 12 |
| 28°F | May 20 | May 6 | Apr 26 | Sep 28 | Oct 9 | Oct 20 |
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 Monument, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 6 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.
Monument planting FAQ
When is the last spring frost in Monument, CO?
Monument's average last spring frost falls near May 17 — the 50% mark at 32°F in the 1991–2020 normals. Hold tender transplants until the risk has passed, then plant out.
When is the first fall frost in Monument, CO?
The first fall frost in Monument typically arrives around October 1 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Monument in?
Monument 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 Monument?
Monument has about 137 frost-free days — a short growing season — between the average last spring frost (May 17) and first fall frost (October 1).
When should I plant tomatoes in Monument?
For Monument, sow tomatoes indoors about March 22–April 5 and move the seedlings out around May 24, after the last spring frost.
Never miss a window in Monument
An email when it’s time to start seeds, transplant, and sow — timed to Monument’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Black Forest · 14 km
- Colorado Springs · 24 km
- Cimarron Hills · 27 km
- Castle Rock · 34 km
- Security-Widefield · 38 km
- The Pinery · 42 km
- Castle Pines · 43 km
- Fort Carson · 44 km
Frost dates recorded at MONUMENT 3S, 3 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 Monument, CO — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00055733. Retrieved from https://blissgarden.com/colorado/monument.