When to plant in Centennial, CO
USDA Zone 6aEverything below — frost dates, hardiness zone, and what to plant when in Centennial, Colorado — is derived from the closest NOAA station with complete climate normals.
Zone 6a means Centennial sees real winter cold, but a good range of perennials survive; the frost dates above govern when annual vegetables go out.
Frost probability
DENVER CENTENNIAL AP · 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 Centennial’s own odds, recorded at DENVER CENTENNIAL AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 30 | May 15 | May 3 | Sep 17 | Oct 1 | Oct 12 |
| 32°F | May 17 | May 5 | Apr 24 | Sep 25 | Oct 8 | Oct 20 |
| 28°F | May 9 | Apr 25 | Apr 10 | Oct 4 | Oct 17 | Oct 28 |
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 Centennial, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 13 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.
Centennial planting FAQ
When is the last spring frost in Centennial, CO?
Centennial's average last spring frost falls near May 5 — 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 Centennial, CO?
In Centennial, the first 32°F freeze of fall lands around October 8 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Centennial in?
Centennial is in USDA hardiness zone 6a. In zone 6a, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Centennial?
There are roughly 156 frost-free days in Centennial (a moderate growing season), running from the average last frost around May 5 to the first fall frost near October 8.
When should I plant tomatoes in Centennial?
In Centennial, start tomato seeds indoors around March 10–March 24, then transplant seedlings outdoors around May 12 once the danger of frost has passed.
Never miss a window in Centennial
An email when it’s time to start seeds, transplant, and sow — timed to Centennial’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Cherry Creek · 2 km
- Greenwood Village · 5 km
- Lone Tree · 7 km
- Four Square Mile · 10 km
- Highlands Ranch · 11 km
- Parker · 12 km
- Englewood · 13 km
- Littleton · 13 km
Frost dates recorded at DENVER CENTENNIAL AP, 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 Centennial, CO — Frost Dates & Zone 6a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00093067. Retrieved from https://blissgarden.com/colorado/centennial.