Commerce City, Colorado planting calendar and frost dates
Commerce City is in USDA hardiness zone 6a. The last spring frost typically comes around May 4 and the first fall frost around October 8, giving about 156 frost-free days a year.
- Typical last frost
- May 4
- Typical first frost
- October 8
- Frost-free season
- 156 days
Frost dates in Commerce City
Last spring frost
- April 20Risky: frost later than this in 9 years out of 10
- May 4Typical: a later frost in half of years
- May 16Safe: a later frost only 1 year in 10
First fall frost
- September 25Risky: frost earlier than this 1 year in 10
- October 8Typical: an earlier frost in half of years
- October 20Late: frost before this in 9 years out of 10
The growing season between the typical last and first frosts is about 156 days. Frost here means a low of 32°F at the weather station. A hard freeze (28°F), which damages most hardy crops too, typically ends around April 22 and returns around October 18.
NOAA U.S. Climate Normals 1991-2020 for Denver-Stapleton, 8 miles SSW of the city center and 108 feet higher. Low-lying and rural spots often frost later in spring and earlier in fall than airports and city centers.
What to plant each month in Commerce City
January
Start indoors: onions
February
Start indoors: broccoli, cabbages, cauliflower, collard greens, kale, leeks, onions, oregano, parsley, petunias, ranunculus, rosemary, snapdragons
March
Start indoors: black-eyed susans, broccoli, cabbages, cauliflower, celery, chives, cilantro, collard greens, eggplants, ginger, kale, leeks, lettuce, marigolds, nasturtiums, oregano, parsley, peppers, petunias, ranunculus, rosemary, sage, snapdragons, spinach, swiss chard, tomatoes
Plant or sow outdoors: black-eyed susans, blueberries, garlic, grapes, grass seed, hollyhocks, kale, onions, peas, poppies, raspberries, rhubarb, strawberries, turnips, wildflowers
April
Start indoors: basil, cantaloupes, cilantro, cosmos, cucumbers, eggplants, marigolds, nasturtiums, okra, peppers, pumpkins, ranunculus, tomatoes, watermelons, winter squash, zucchini
Plant or sow outdoors: asparagus, beets, black-eyed susans, blackberries, blueberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, collard greens, dahlias, dill, figs, garlic, gladioli, grapes, grass seed, green onions, hollyhocks, kale, leeks, lettuce, onions, parsley, peas, poppies, potatoes, radishes, ranunculus, raspberries, rhubarb, roses, snapdragons, spinach, strawberries, swiss chard, turnips, wildflowers
May
Start indoors: cantaloupes, cosmos, cucumbers, okra, pumpkins, watermelons, winter squash, zinnias, zucchini
Plant or sow outdoors: asparagus, basil, beets, cantaloupes, carrots, chives, cilantro, cucumbers, dahlias, dill, eggplants, figs, garden mums, ginger, gladioli, grapes, green beans, green onions, kentucky bluegrass, lavenders, leeks, lettuce, lilies, marigolds, mints, nasturtiums, oregano, parsley, peppers, perennial ryegrass, petunias, potatoes, pumpkins, ranunculus, rosemary, roses, sage, snapdragons, spinach, sunflowers, sweet corn, sweet peas, swiss chard, tall fescue, thyme, tomatoes, watermelons, winter squash, zucchini
June
Plant or sow outdoors: asparagus, bermudagrass, cantaloupes, celery, centipedegrass, cosmos, cucumbers, eggplants, garden mums, green beans, green onions, okra, peanuts, peppers, pumpkins, st. augustinegrass, sweet potatoes, tomatoes, watermelons, winter squash, zinnias, zoysiagrass, zucchini
July
Plant or sow outdoors: bermudagrass, centipedegrass, green onions, st. augustinegrass, zinnias, zoysiagrass
Plant for fall: bearded irises, beets, broccoli, brussels sprouts, cabbages, carrots, cauliflower, collard greens, lettuce, peas, radishes, snapdragons, spinach, swiss chard, turnips
August
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, carrots, cauliflower, clematis, coneflowers, crocuses, daffodils, daylilies, grass seed, hostas, hydrangeas, kale, lettuce, lilies, ornamental alliums, peonies, radishes, roses, saffron, snapdragons, spinach, swiss chard, tulips, turnips
September
Plant for fall: cabbages, cauliflower, crocuses, daffodils, daylilies, grass seed, hostas, hyacinths, kale, lilies, ornamental alliums, peonies, radishes, saffron, spinach, tulips
October
Plant for fall: crocuses, daffodils, garlic, hyacinths, lilies, ornamental alliums, peonies, tulips
Frost dates and zones by ZIP code in Commerce City
Commerce City's 3 main ZIP codes take their frost dates from 2 different NOAA stations: the typical last frost ranges from May 2 in 80603 to May 4 in 80022. The hardiness zone is 5b in 80603, 80640, and 6a in 80022.
| ZIP code | Zone | Weather station | Typical last frost | Typical first frost |
|---|---|---|---|---|
| 80022 | 6a | Denver-Stapleton, 8 mi SSW | May 4 | Oct 8 |
| 80603 | 5b | Northglenn, 3.1 mi NW | May 2 | Oct 11 |
| 80640 | 5b | Northglenn, 3.1 mi NW | May 2 | Oct 11 |
Denver-Stapleton also supplies the frost dates for Denver and Aurora, so their planting calendars match Commerce City's.
Planting dates for popular crops in Commerce City
| Plant | Start indoors | Plant or sow outdoors | Fall planting |
|---|---|---|---|
| Tomatoes | Mar 27 to Apr 10 | May 22 to Jun 5 | — |
| Strawberries | — | Mar 23 to Apr 6 | — |
| Lettuce | Mar 9 to 23 | Apr 27 to May 11 | Jul 9 to Aug 13 |
| Cilantro | Mar 23 to Apr 6 | May 4 to 11 | — |
| Basil | Apr 3 to 17 | May 22 to 29 | — |
| Potatoes | — | Apr 26 to May 3 | — |
| Garlic | — | Mar 23 to Apr 6 | Oct 8 to 22 |
| Onions | Jan 12 to Feb 23 | Apr 6 to 20 | — |
| Cucumbers | Apr 24 to May 8 | May 22 to Jun 5 | — |
| Pumpkins | Apr 24 to May 8 | May 22 to Jun 5 | — |
| Peppers | Mar 6 to Apr 3 | May 22 to Jun 5 | — |
| Carrots | — | Apr 13 to May 4 | Jul 16 to Aug 6 |
| Sweet Potatoes | — | Jun 5 to 12 | — |
| Watermelons | Apr 17 to May 1 | May 22 to Jun 5 | — |
| Sweet Corn | — | May 4 to 18 | — |
| Green Beans | — | May 22 to Jun 5 | — |
| Zucchini | Apr 24 to May 8 | May 22 to Jun 5 | — |
| Broccoli | Feb 16 to Mar 9 | Apr 6 to 20 | Jul 23 to Aug 20 |
| Peas | — | Mar 23 to Apr 6 | Jul 16 to 30 |
| Spinach | Mar 23 to 30 | Apr 27 to May 11 | Jul 30 to Sep 3 |
| Sunflowers | — | May 4 to 25 | — |
| Zinnias | May 23 to 30 | Jun 20 to Jul 4 | — |
| Tulips | — | — | Aug 27 to Oct 22 |
| Daffodils | — | — | Aug 27 to Oct 8 |
| Grass Seed | — | Mar 23 to Apr 6 | Aug 27 to Sep 10 |
Nearby cities
- Thornton, CO zone 6a, last frost May 2
- Denver, CO zone 6a, last frost May 4
- Aurora, CO zone 6a, last frost May 4
- Westminster, CO zone 6a, last frost May 2
- Broomfield, CO zone 6a, last frost May 2
- Arvada, CO zone 6a, last frost May 5
Planting in ColoradoAbout zone 6aPrintable calendar for Commerce City
Questions
When is the last frost in Commerce City?
Around May 4 in a typical year, based on NOAA's 1991-2020 records for Denver-Stapleton. There is still a 1 in 10 chance of frost after May 16.
What planting zone is Commerce City in?
USDA hardiness zone 6a (2023 map), with parts of the city in zone 5b. The zone tells you which perennials survive the winter; planting dates depend on frost dates instead.
When should I plant tomatoes in Commerce City?
Start seeds indoors March 27 to April 10 and set plants out May 22 to June 5.
When is the first frost in Commerce City?
Around October 8 in a typical year, and before September 25 about 1 year in 10.