Denver Frost Dates
Denver, CO · USDA Zone 6a
Median (50 percent probability) dates of the last spring and first fall 32°F freeze at Denver International Airport, from NOAA 1991-2020 US Climate Normals (station USW00003017).
Denver is in USDA Zone 6a. Plan tender crops around the average last frost (~May) and wrap up before the first fall frost (~October).
Denver planting calendar
| Crop | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Tomatoes | ● | ● | ● | |||||||||
| Peppers | ● | ● | ● | |||||||||
| Cucumbers | ● | ● | ● | |||||||||
| Lettuce | ● | ● | ||||||||||
| Zucchini | ● | ● | ● | |||||||||
| Carrots | ● | ● | ||||||||||
| Beans (bush) | ● | ● | ||||||||||
| Peas | ● | ● | ||||||||||
| Broccoli | ● | ● | ● | |||||||||
| Spinach | ● | ● | ||||||||||
| Kale | ● | ● | ● | |||||||||
| Onions | ● | ● | ● | |||||||||
| Garlic | ||||||||||||
| Potatoes | ● | ● | ||||||||||
| Squash (winter) | ● | ● | ● | |||||||||
| Corn | ● | ● | ||||||||||
| Radishes | ● | ● | ||||||||||
| Beets | ● | ● | ||||||||||
| Eggplant | ● | ● | ● | |||||||||
| Basil | ● | ● | ● | |||||||||
| Cilantro | ● | ● | ||||||||||
| Parsley | ● | ● | ● | |||||||||
| Pumpkins | ● | ● | ● | |||||||||
| Sunflowers | ● | ● |
Fall planting in Denver
The Denver average first frost is around October 9, which is what sets the fall deadlines below. Each crop needs its days to maturity plus about two weeks for the slower growth of shortening days, minus whatever it can take once light frost arrives.
| Crop | Sow by | Harvest |
|---|---|---|
| Radishes | Sep 18 | Oct 16 |
| Cilantro | Aug 25 | Oct 9 |
| Kale | Aug 24 | Oct 23 |
| Beets | Aug 22 | Oct 16 |
| Lettuce | Aug 20 | Oct 9 |
| Carrots | Aug 14 | Oct 23 |
| Broccoli | Aug 12 | Oct 16 |
| Peas | Aug 10 | Oct 9 |
| Zucchini | Jul 18 | Sep 11 |
| Beans (bush) | Jul 18 | Sep 11 |
| Cucumbers | Jul 13 | Sep 11 |
| Potatoes | Jul 7 | Oct 5 |
Planted in fall to overwinter in Denver: garlic ( Oct 9 to Nov 6) , onions ( Aug 28 to Sep 18) , spinach ( Aug 28 to Sep 11) , parsley ( Aug 28 to Sep 11) . See when to plant garlic and the fall planting calendar by zone.
Planning around Denver's frost dates
- What to plant in October by zone
The October sowing and planting list for Denver.
- What to plant in November by zone
What still goes in the ground in November in Denver.
- Cold frame gardening by zone
How many weeks a cold frame adds to the Denver season, and what to grow in it.
- October garden checklist
The jobs to finish before the first hard freeze in Denver.
- Houseplants for low light
Something to grow while the Denver garden is frozen.
More frost dates
Also in Zone 6a: Chicago, IL . Other cities: New York, NY , Los Angeles, CA , Houston, TX , Phoenix, AZ , Philadelphia, PA , Atlanta, GA , Dallas, TX , Seattle, WA , Minneapolis, MN , Miami, FL .
Frequently asked questions
When is the last frost in Denver?
On average, around May.
What planting zone is Denver, CO?
Denver is in USDA hardiness Zone 6a.
When is the first frost in Denver?
On average, around October 9. That is a 50 percent probability from the 1991-2020 NOAA normals, so half of all years see a freeze before it.
What can I plant in the fall in Denver?
radishes (sow by Sep 18), cilantro (sow by Aug 25), kale (sow by Aug 24), beets (sow by Aug 22), lettuce (sow by Aug 20), carrots (sow by Aug 14). Each date is counted back from the Denver first frost around October 9.