Frost Dates for Carbondale, CO 81623
Last spring frost July 6 · First fall frost August 21 · 46 frost-free days · USDA Zone 6a
ZIP 81623 has about 15,100 people.
Short season: 46 frost-free days. Spring frost risk spans June 19–July 23 (34 days). Fall frost risk spans August 1–September 10 (40 days).
Frost probability for 81623
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | July 23 | July 6 | June 19 |
| Fall (first frost) | August 1 | August 21 | September 10 |
Dates come from NOAA 1971–2000 freeze probabilities at MEREDITH (42.2 km away); the 50% date is the median year.
Which crops fit a 46-day season in Carbondale
In Carbondale (46 frost-free days, a short season), 16 of 56 planner crops fit outright, 3 get two plantings, 6 need an indoor start, 30 don't reliably mature, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Jun 1 | Jul 20–Jul 27 | 4 | no-fit: Needs 80 days; Carbondale has 4 after Jul 20. | — |
| Pepper | May 25 | Jul 20–Jul 27 | 4 | no-fit: Needs 75 days; Carbondale has 4 after Jul 20. | — |
| Lettuce | May 11 | Jun 8–Jun 15 | 81 | fits: 45 days to maturity, 81 available after Jun 8. | Jun 30 |
| Carrots | — | Jun 15–Jun 22 | 88 | fits: 70 days to maturity, 88 available after Jun 15. | Jun 19 |
| Cucumber | Jun 15 | Jul 20–Jul 27 | 18 | no-fit: Needs 60 days; Carbondale has 18 after Jul 20. | — |
| Beans | — | Jul 13–Jul 27 | 32 | no-fit: Needs 60 days; Carbondale has 32 after Jul 13. | — |
| Peas | — | May 11–Jul 20 | 109 | fits: 65 days to maturity, 109 available after May 11. | Jun 10 |
| Zucchini | Jun 22 | Jul 20–Jul 27 | 18 | no-fit: Needs 55 days; Carbondale has 18 after Jul 20. | — |
| Onion | Apr 13 | Jun 8–Jun 22 | 81 | head-start: Even planted out Jun 8, the outdoor season is about 19 days short; choose an early variety or grow under cover. | — |
| Spinach | — | May 11–Jun 29 | 123 | two-plantings: Plant May 11 and again by Jul 19; both mature before Sep 11. | Jul 19 |
| Kale | Apr 27 | Jun 8–Jun 22 | 95 | fits: 55 days to maturity, 95 available after Jun 8. | Jul 4 |
| Broccoli | May 11 | Jun 8–Jun 22 | 81 | fits: 80 days to maturity, 81 available after Jun 8. | — |
| Cabbage | May 11 | Jun 8–Jun 22 | 95 | fits: 70 days to maturity, 95 available after Jun 8. | Jun 19 |
| Radish | — | May 11–Aug 3 | 109 | two-plantings: Plant May 11 and again by Jul 20; both mature before Aug 28. | Jul 20 |
| Beets | — | May 11–Aug 3 | 109 | fits: 55 days to maturity, 109 available after May 11. | Jun 20 |
| Potatoes | — | Jun 22–Jun 29 | 67 | no-fit: Needs 90 days; Carbondale has 67 after Jun 22. | — |
| Garlic | — | Aug 21 | 151 | overwinter: Plant Aug 21 to Sep 11; harvest the following summer. | Sep 11 |
| Strawberry | — | Jun 1–Jul 27 | 102 | perennial: A perennial: plant Jun 1; it fruits from the following year and keeps producing for several years. | — |
| Corn | Jun 8 | Jul 13–Jul 20 | 18 | no-fit: Needs 75 days; Carbondale has 18 after Jul 13. | — |
| Pumpkin | Jun 22 | Jul 20–Jul 20 | 11 | no-fit: Needs 100 days; Carbondale has 11 after Jul 20. | — |
| Cauliflower | May 25 | Jun 29–Jul 13 | 60 | head-start: Even planted out Jun 29, the outdoor season is about 15 days short; choose an early variety or grow under cover. | — |
| Swiss Chard | May 11 | Jun 22–Jun 22 | 67 | fits: 55 days to maturity, 67 available after Jun 22. | — |
| Arugula | — | May 11–Aug 3 | 123 | two-plantings: Plant May 11 and again by Jul 19; both mature before Sep 11. | Jul 19 |
| Brussel Sprouts | May 11 | Jun 8–Jun 22 | 95 | head-start: Even planted out Jun 8, the outdoor season is about 5 days short; choose an early variety or grow under cover. | — |
| Butternut Squash | Jun 22 | Jul 20–Jul 27 | 11 | no-fit: Needs 100 days; Carbondale has 11 after Jul 20. | — |
| Eggplant | May 18 | Jul 20–Jul 27 | 4 | no-fit: Needs 70 days; Carbondale has 4 after Jul 20. | — |
| Okra | Jun 8 | Jul 13–Jul 20 | 25 | no-fit: Needs 55 days; Carbondale has 25 after Jul 13. | — |
| Basil | Jun 1 | Jul 27–Jul 27 | 11 | no-fit: Needs 60 days; Carbondale has 11 after Jul 27. | — |
| Cilantro | — | Jun 8–Jun 29 | 81 | fits: 50 days to maturity, 81 available after Jun 8. | Jun 25 |
| Parsley | Apr 27 | Jul 13–Jul 20 | 46 | no-fit: Needs 70 days; Carbondale has 46 after Jul 13. | — |
| Celery | Apr 27 | Jul 13–Jul 27 | 46 | no-fit: Needs 120 days; Carbondale has 46 after Jul 13. | — |
| Scallions | Apr 27 | Jun 8–Jun 22 | 95 | fits: 60 days to maturity, 95 available after Jun 8. | Jun 29 |
| Turnip | — | Jun 8–Jun 22 | 95 | fits: 50 days to maturity, 95 available after Jun 8. | Jul 9 |
| Kohlrabi | — | May 25–Jun 8 | 109 | fits: 55 days to maturity, 109 available after May 25. | Jul 4 |
| Bok Choy | Jun 8 | Jun 29–Jul 6 | 60 | fits: 45 days to maturity, 60 available after Jun 29. | Jun 30 |
| Collards | Apr 27 | Jun 8–Jun 22 | 95 | fits: 60 days to maturity, 95 available after Jun 8. | Jun 29 |
| Cantaloupe | Jun 22 | Jul 20–Jul 27 | 4 | no-fit: Needs 85 days; Carbondale has 4 after Jul 20. | — |
| Chives | Apr 13 | Jul 13–Jul 20 | 60 | no-fit: Needs 90 days; Carbondale has 60 after Jul 13. | — |
| Dill | — | May 11–Aug 3 | 109 | fits: 55 days to maturity, 109 available after May 11. | Jun 20 |
| Oregano | Apr 27 | Jul 13–Jul 20 | 60 | head-start: Even planted out Jul 13, the outdoor season is about 20 days short; choose an early variety or grow under cover. | — |
| Rosemary | Apr 13 | Jul 13–Jul 20 | 46 | no-fit: Needs 80 days; Carbondale has 46 after Jul 13. | — |
| Sage | May 11 | Jul 13–Jul 20 | 60 | head-start: Even planted out Jul 13, the outdoor season is about 15 days short; choose an early variety or grow under cover. | — |
| Thyme | Apr 27 | Jul 13–Jul 20 | 60 | no-fit: Needs 90 days; Carbondale has 60 after Jul 13. | — |
| Calendula | May 25 | Jun 22–Jul 6 | 67 | fits: 50 days to maturity, 67 available after Jun 22. | Jun 25 |
| Cosmos | Jun 8 | Jul 6–Jul 20 | 32 | no-fit: Needs 60 days; Carbondale has 32 after Jul 6. | — |
| Lavender | Apr 13 | Jul 6–Jul 20 | 67 | no-fit: Needs 90 days; Carbondale has 67 after Jul 6. | — |
| Marigolds | May 25 | Jul 6–Jul 13 | 32 | head-start: Even planted out Jul 6, the outdoor season is about 18 days short; choose an early variety or grow under cover. | — |
| Melons | Jun 22 | Jul 20–Jul 27 | 4 | no-fit: Needs 85 days; Carbondale has 4 after Jul 20. | — |
| Mint | — | Jul 6–Jul 20 | 67 | no-fit: Needs 90 days; Carbondale has 67 after Jul 6. | — |
| Nasturtiums | Jun 8 | Jul 6–Jul 13 | 32 | no-fit: Needs 55 days; Carbondale has 32 after Jul 6. | — |
| Pole Beans | — | Jul 13–Jul 27 | 25 | no-fit: Needs 65 days; Carbondale has 25 after Jul 13. | — |
| Spaghetti Squash | Jun 22 | Jul 20–Jul 27 | 11 | no-fit: Needs 90 days; Carbondale has 11 after Jul 20. | — |
| Sunflowers | — | Jul 6–Jul 20 | 32 | no-fit: Needs 70 days; Carbondale has 32 after Jul 6. | — |
| Tomatillos | May 11 | Jul 13–Jul 20 | 11 | no-fit: Needs 75 days; Carbondale has 11 after Jul 13. | — |
| Watermelon | Jun 22 | Jul 13–Jul 20 | 11 | no-fit: Needs 80 days; Carbondale has 11 after Jul 13. | — |
| Yellow Squash | Jun 22 | Jul 20–Jul 27 | 18 | no-fit: Needs 55 days; Carbondale has 18 after Jul 20. | — |
| Zinnias | Jun 8 | Jul 6–Jul 20 | 32 | no-fit: Needs 60 days; Carbondale has 32 after Jul 6. | — |
Month by month in Carbondale
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start the slowest-growing crops indoors: onions, leeks, and celery (10–12 weeks before last frost). |
| March | Organize planting supplies and seed-starting mix. Check stored garden tools. |
| April | Start indoors: Chives (Apr 13), Lavender (Apr 13), Onion (Apr 13), Rosemary (Apr 13), Celery (Apr 27), Collards (Apr 27), +5 more. |
| May | Start indoors: Broccoli (May 11), Brussel Sprouts (May 11), Cabbage (May 11), Lettuce (May 11), Sage (May 11), Swiss Chard (May 11), +6 more. Direct sow from: Arugula (May 11), Beets (May 11), Dill (May 11), Peas (May 11), Radish (May 11), Spinach (May 11), +1 more. |
| June | Start indoors: Basil (Jun 1), Tomato (Jun 1), Bok Choy (Jun 8), Corn (Jun 8), Cosmos (Jun 8), Nasturtiums (Jun 8), +11 more. Direct sow from: Cilantro (Jun 8), Turnip (Jun 8), Carrots (Jun 15), Potatoes (Jun 22). Transplant from: Broccoli (Jun 8), Brussel Sprouts (Jun 8), Cabbage (Jun 8), Collards (Jun 8), Kale (Jun 8), Lettuce (Jun 8), +6 more. Plant: Strawberry (Jun 1). Last sowing dates: Peas (Jun 10), Cabbage (Jun 19), Carrots (Jun 19), Beets (Jun 20), Dill (Jun 20), Calendula (Jun 25), +5 more. |
| July | Direct sow from: Sunflowers (Jul 6), Beans (Jul 13), Pole Beans (Jul 13). Transplant from: Cosmos (Jul 6), Lavender (Jul 6), Marigolds (Jul 6), Mint (Jul 6), Nasturtiums (Jul 6), Zinnias (Jul 6), +23 more. Last frost around July 6. Last sowing dates: Kale (Jul 4), Kohlrabi (Jul 4), Turnip (Jul 9), Arugula (Jul 19), Spinach (Jul 19), Radish (Jul 20). |
| August | Direct sow from: Garlic (Aug 21). First frost around August 21. |
| September | Last sowing dates: Garlic (Sep 11). |
| October | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
| November | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
| 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 Carbondale, CO (ZIP 81623)?
The median last spring frost date for Carbondale, CO (ZIP code 81623) is around July 6. 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 June 19; one in ten it runs past July 23.
What is the first fall frost date in Carbondale, CO?
The median first fall frost date for Carbondale, CO is around August 21. 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 August 1 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Carbondale, CO?
The frost-free growing season in Carbondale is about 46 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 Carbondale (46 frost-free days, a short season), 16 of 56 planner crops fit outright, 3 get two plantings, 6 need an indoor start, 30 don't reliably mature, 1 crop is perennial.
What USDA hardiness zone is Carbondale, CO?
Carbondale, 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 Carbondale, CO?
Start tomatoes indoors Jun 1 and plant out Jul 20 in Carbondale. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Carbondale?
One spring planting around Jun 8. The last sow date is Jun 30.
When do I plant garlic in Carbondale?
Aug 21 to Sep 11; it overwinters and is ready the following summer.
Can I grow Celery in Carbondale?
Not reliably outdoors. Needs 120 days; Carbondale has 46 after Jul 13.
Which nearby ZIP has a longer season?
Glenwood Springs (ZIP 81601) has 122 frost-free days, 76 more than Carbondale (ZIP 81623). See Glenwood Springs ZIP 81601 frost dates
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