Frost Dates for Denver, CO 80226
Denver has 43 ZIP codes. The Denver, CO frost page lists all of them with their dates.
Last spring frost May 9 · First fall frost October 1 · 145 frost-free days · USDA Zone 6a
ZIP 80226 has about 31,600 people, one of 43 ZIP codes in Denver.
Moderate season: 145 frost-free days. Spring frost risk spans April 24–May 24 (30 days). Fall frost risk spans September 18–October 14 (26 days).
Frost probability for 80226
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 24 | May 9 | April 24 |
| Fall (first frost) | September 18 | October 1 | October 14 |
Dates come from NOAA 1971–2000 freeze probabilities at LAKEWOOD (4.9 km away); the 50% date is the median year.
Which crops fit a 145-day season in Denver
In Denver (145 frost-free days, a moderate season), 37 of 56 planner crops fit outright, 18 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Apr 4 | May 23–May 30 | 103 | fits: 80 days to maturity, 103 available after May 23. | Jun 1 |
| Pepper | Mar 28 | May 23–May 30 | 103 | fits: 75 days to maturity, 103 available after May 23. | Jun 6 |
| Lettuce | Mar 14 | Apr 11–Apr 18 | 180 | two-plantings: Plant Apr 11 and again by Aug 10; both mature before Oct 8. | Aug 10 |
| Carrots | — | Apr 18–Apr 25 | 187 | fits: 70 days to maturity, 187 available after Apr 18. | Jul 30 |
| Cucumber | Apr 18 | May 23–May 30 | 117 | fits: 60 days to maturity, 117 available after May 23. | Jul 5 |
| Beans | — | May 16–May 30 | 131 | fits: 60 days to maturity, 131 available after May 16. | Jul 12 |
| Peas | — | Mar 14–May 23 | 208 | fits: 65 days to maturity, 208 available after Mar 14. | Jul 21 |
| Zucchini | Apr 25 | May 23–May 30 | 117 | fits: 55 days to maturity, 117 available after May 23. | Jul 10 |
| Onion | Feb 14 | Apr 11–Apr 25 | 180 | fits: 100 days to maturity, 180 available after Apr 11. | — |
| Spinach | — | Mar 14–May 2 | 222 | two-plantings: Plant Mar 14 and again by Aug 29; both mature before Oct 22. | Aug 29 |
| Kale | Feb 28 | Apr 11–Apr 25 | 194 | two-plantings: Plant Apr 11 and again by Aug 14; both mature before Oct 22. | Aug 14 |
| Broccoli | Mar 14 | Apr 11–Apr 25 | 180 | fits: 80 days to maturity, 180 available after Apr 11. | Jul 6 |
| Cabbage | Mar 14 | Apr 11–Apr 25 | 194 | fits: 70 days to maturity, 194 available after Apr 11. | Jul 30 |
| Radish | — | Mar 14–Jun 6 | 208 | two-plantings: Plant Mar 14 and again by Aug 30; both mature before Oct 8. | Aug 30 |
| Beets | — | Mar 14–Jun 6 | 208 | two-plantings: Plant Mar 14 and again by Jul 31; both mature before Oct 8. | Jul 31 |
| Potatoes | — | Apr 25–May 2 | 166 | fits: 90 days to maturity, 166 available after Apr 25. | — |
| Garlic | — | Oct 1 | 250 | overwinter: Plant Oct 1 to Oct 22; harvest the following summer. | Oct 22 |
| Strawberry | — | Apr 4–May 30 | 201 | perennial: A perennial: plant Apr 4; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 11 | May 16–May 23 | 117 | fits: 75 days to maturity, 117 available after May 16. | Jun 13 |
| Pumpkin | Apr 25 | May 23–May 23 | 110 | fits: 100 days to maturity, 110 available after May 23. | — |
| Cauliflower | Mar 28 | May 2–May 16 | 159 | fits: 75 days to maturity, 159 available after May 2. | Jul 11 |
| Swiss Chard | Mar 14 | Apr 25–Apr 25 | 166 | two-plantings: Plant Apr 25 and again by Jul 31; both mature before Oct 8. | Jul 31 |
| Arugula | — | Mar 14–Jun 6 | 222 | two-plantings: Plant Mar 14 and again by Aug 29; both mature before Oct 22. | Aug 29 |
| Brussel Sprouts | Mar 14 | Apr 11–Apr 25 | 194 | fits: 100 days to maturity, 194 available after Apr 11. | Jun 30 |
| Butternut Squash | Apr 25 | May 23–May 30 | 110 | fits: 100 days to maturity, 110 available after May 23. | — |
| Eggplant | Mar 21 | May 23–May 30 | 103 | fits: 70 days to maturity, 103 available after May 23. | Jun 11 |
| Okra | Apr 11 | May 16–May 23 | 124 | two-plantings: Plant May 16 and again by Jul 10; both mature before Sep 17. | Jul 10 |
| Basil | Apr 4 | May 30–May 30 | 110 | fits: 60 days to maturity, 110 available after May 30. | Jul 5 |
| Cilantro | — | Apr 11–May 2 | 180 | two-plantings: Plant Apr 11 and again by Aug 5; both mature before Oct 8. | Aug 5 |
| Parsley | Feb 28 | May 16–May 23 | 145 | fits: 70 days to maturity, 145 available after May 16. | Jul 16 |
| Celery | Feb 28 | May 16–May 30 | 145 | fits: 120 days to maturity, 145 available after May 16. | May 27 |
| Scallions | Feb 28 | Apr 11–Apr 25 | 194 | two-plantings: Plant Apr 11 and again by Aug 9; both mature before Oct 22. | Aug 9 |
| Turnip | — | Apr 11–Apr 25 | 194 | two-plantings: Plant Apr 11 and again by Aug 19; both mature before Oct 22. | Aug 19 |
| Kohlrabi | — | Mar 28–Apr 11 | 208 | two-plantings: Plant Mar 28 and again by Aug 14; both mature before Oct 22. | Aug 14 |
| Bok Choy | Apr 11 | May 2–May 9 | 159 | two-plantings: Plant May 2 and again by Aug 10; both mature before Oct 8. | Aug 10 |
| Collards | Feb 28 | Apr 11–Apr 25 | 194 | two-plantings: Plant Apr 11 and again by Aug 9; both mature before Oct 22. | Aug 9 |
| Cantaloupe | Apr 25 | May 23–May 30 | 103 | fits: 85 days to maturity, 103 available after May 23. | May 27 |
| Chives | Feb 14 | May 16–May 23 | 159 | fits: 90 days to maturity, 159 available after May 16. | — |
| Dill | — | Mar 14–Jun 6 | 208 | two-plantings: Plant Mar 14 and again by Jul 31; both mature before Oct 8. | Jul 31 |
| Oregano | Feb 28 | May 16–May 23 | 159 | fits: 80 days to maturity, 159 available after May 16. | — |
| Rosemary | Feb 14 | May 16–May 23 | 145 | fits: 80 days to maturity, 145 available after May 16. | — |
| Sage | Mar 14 | May 16–May 23 | 159 | fits: 75 days to maturity, 159 available after May 16. | — |
| Thyme | Feb 28 | May 16–May 23 | 159 | fits: 90 days to maturity, 159 available after May 16. | — |
| Calendula | Mar 28 | Apr 25–May 9 | 166 | two-plantings: Plant Apr 25 and again by Aug 5; both mature before Oct 8. | Aug 5 |
| Cosmos | Apr 11 | May 9–May 23 | 131 | fits: 60 days to maturity, 131 available after May 9. | Jul 5 |
| Lavender | Feb 14 | May 9–May 23 | 166 | fits: 90 days to maturity, 166 available after May 9. | — |
| Marigolds | Mar 28 | May 9–May 16 | 131 | two-plantings: Plant May 9 and again by Jul 15; both mature before Sep 17. | Jul 15 |
| Melons | Apr 25 | May 23–May 30 | 103 | fits: 85 days to maturity, 103 available after May 23. | May 27 |
| Mint | — | May 9–May 23 | 166 | fits: 90 days to maturity, 166 available after May 9. | — |
| Nasturtiums | Apr 11 | May 9–May 16 | 131 | two-plantings: Plant May 9 and again by Jul 10; both mature before Sep 17. | Jul 10 |
| Pole Beans | — | May 16–May 30 | 124 | fits: 65 days to maturity, 124 available after May 16. | Jun 30 |
| Spaghetti Squash | Apr 25 | May 23–May 30 | 110 | fits: 90 days to maturity, 110 available after May 23. | May 29 |
| Sunflowers | — | May 9–May 23 | 131 | fits: 70 days to maturity, 131 available after May 9. | Jun 25 |
| Tomatillos | Mar 14 | May 16–May 23 | 110 | fits: 75 days to maturity, 110 available after May 16. | Jun 6 |
| Watermelon | Apr 25 | May 16–May 23 | 110 | fits: 80 days to maturity, 110 available after May 16. | Jun 1 |
| Yellow Squash | Apr 25 | May 23–May 30 | 117 | fits: 55 days to maturity, 117 available after May 23. | Jul 10 |
| Zinnias | Apr 11 | May 9–May 23 | 131 | fits: 60 days to maturity, 131 available after May 9. | Jul 5 |
Month by month in Denver
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 14), Lavender (Feb 14), Onion (Feb 14), Rosemary (Feb 14), Celery (Feb 28), Collards (Feb 28), +5 more. |
| March | Start indoors: Broccoli (Mar 14), Brussel Sprouts (Mar 14), Cabbage (Mar 14), Lettuce (Mar 14), Sage (Mar 14), Swiss Chard (Mar 14), +6 more. Direct sow from: Arugula (Mar 14), Beets (Mar 14), Dill (Mar 14), Peas (Mar 14), Radish (Mar 14), Spinach (Mar 14), +1 more. |
| April | Start indoors: Basil (Apr 4), Tomato (Apr 4), Bok Choy (Apr 11), Corn (Apr 11), Cosmos (Apr 11), Nasturtiums (Apr 11), +11 more. Direct sow from: Cilantro (Apr 11), Turnip (Apr 11), Carrots (Apr 18), Potatoes (Apr 25). Transplant from: Broccoli (Apr 11), Brussel Sprouts (Apr 11), Cabbage (Apr 11), Collards (Apr 11), Kale (Apr 11), Lettuce (Apr 11), +4 more. Plant: Strawberry (Apr 4). |
| May | Direct sow from: Sunflowers (May 9), Beans (May 16), Pole Beans (May 16). Transplant from: Bok Choy (May 2), Cauliflower (May 2), Cosmos (May 9), Lavender (May 9), Marigolds (May 9), Mint (May 9), +25 more. Last frost around May 9. Last sowing dates: Cantaloupe (May 27), Celery (May 27), Melons (May 27), Spaghetti Squash (May 29). |
| June | Last sowing dates: Tomato (Jun 1), Watermelon (Jun 1), Pepper (Jun 6), Tomatillos (Jun 6), Eggplant (Jun 11), Corn (Jun 13), +3 more. |
| July | Last sowing dates: Basil (Jul 5), Cosmos (Jul 5), Cucumber (Jul 5), Zinnias (Jul 5), Broccoli (Jul 6), Nasturtiums (Jul 10), +13 more. |
| August | Last sowing dates: Calendula (Aug 5), Cilantro (Aug 5), Collards (Aug 9), Scallions (Aug 9), Bok Choy (Aug 10), Lettuce (Aug 10), +6 more. |
| September | First fall frost approaching (around October 1). Transplant fall brassicas. Sow spinach, arugula, and radishes. |
| October | Direct sow from: Garlic (Oct 1). First frost around October 1. Last sowing dates: Garlic (Oct 22). |
| November | Harvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year. |
| December | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
Frequently Asked Questions
What is the last frost date for Denver, CO (ZIP 80226)?
The median last spring frost date for Denver, CO (ZIP code 80226) is around May 9. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area. One year in ten frost ends before April 24; one in ten it runs past May 24.
What is the first fall frost date in Denver, CO?
The median first fall frost date for Denver, CO is around October 1. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses. The first frost arrives around September 18 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Denver, CO?
The frost-free growing season in Denver is about 145 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side. In Denver (145 frost-free days, a moderate season), 37 of 56 planner crops fit outright, 18 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Denver, CO?
Denver, CO is in USDA hardiness zone 6a (2023 USDA Plant Hardiness Zone Map). Zones come from the average coldest winter temperature, so they tell you which perennials survive the winter; the frost dates on this page tell you when to plant.
When should I start tomatoes indoors in Denver, CO?
Start tomatoes indoors Apr 4 and plant out May 23 in Denver. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Denver?
Two: plant Apr 11 and again by Aug 10; both mature before Oct 8.
When do I plant garlic in Denver?
Oct 1 to Oct 22; it overwinters and is ready the following summer.
Nearby and related
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