Frost dates for 81623Carbondale, CO
The average last spring frost in Carbondale is June 2 and the average first fall frost is September 23, giving a typical growing season of about 113 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Jun 2
- Average first fall frost
- Sep 23
- Growing season
- 113 days
Safer after Jun 17 (1-in-10 risk)
Possible by Sep 12 (1-in-10 risk)
Last frost typically in 218 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Jun 3 · Jun 16 · Jul 1 | Sep 1 · Sep 14 · Sep 25 | 89 days | 100% |
| Frost / freeze (32°F) | May 17 · Jun 2 · Jun 17 | Sep 12 · Sep 23 · Oct 4 | 113 days | 100% |
| Hard freeze (28°F) | May 3 · May 18 · Jun 5 | Sep 18 · Oct 1 · Oct 16 | 135 days | 100% |
Planting calendar for Carbondale
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | May 2 – Jul 8 |
| Tomatoes | Transplant outdoors | Jun 18 – Jun 3 |
| Peppers | Start seeds indoors | May 2 – Jun 2 |
| Peppers | Transplant outdoors | Jul 2 – Aug 2 |
| Eggplant | Start seeds indoors | May 19 – Jun 17 |
| Eggplant | Transplant outdoors | Jul 2 – Aug 2 |
| Cucumbers | Sow outdoors | Jul 2 – Jun 13 |
| Summer squash | Sow outdoors | Jun 18 – Aug 2 |
| Winter squash & pumpkins | Sow outdoors | Jul 2 – Aug 2 |
| Snap beans | Sow outdoors | Jun 18 – Jul 6 |
| Sweet corn | Sow outdoors | Jun 18 – Jun 3 |
| Watermelon & cantaloupe | Sow outdoors | Jul 2 – Aug 2 |
| Okra | Sow outdoors | Jun 25 – Jul 18 |
| Peas | Sow outdoors (spring) | May 2 – Jun 17 |
| Potatoes | Plant outdoors (spring) | May 2 – Jul 2 |
| Onions | Start seeds indoors (spring) | Mar 21 – Apr 17 |
| Onions | Transplant outdoors (spring) | May 19 – Jun 17 |
| Broccoli | Start seeds indoors (spring) | Apr 14 – May 18 |
| Broccoli | Transplant outdoors (spring) | May 19 – Jun 17 |
| Broccoli | Start seeds indoors (fall) | May 24 – Jun 3 |
| Broccoli | Transplant outdoors (fall) | Jun 23 – Jul 4 |
| Cabbage | Start seeds indoors (spring) | Apr 4 – May 2 |
| Cabbage | Transplant outdoors (spring) | May 2 – Jun 2 |
| Cabbage | Start seeds indoors (fall) | May 14 – Jun 13 |
| Cabbage | Transplant outdoors (fall) | Jun 13 – Jul 14 |
| Leaf lettuce | Sow outdoors (spring) | May 2 – Jul 18 |
| Leaf lettuce | Sow outdoors (fall) | Jun 13 – Jul 30 |
| Spinach | Sow outdoors (spring) | Apr 25 – Jun 8 |
| Spinach | Sow outdoors (fall) | Jun 30 – Aug 4 |
| Radishes | Sow outdoors (spring) | May 2 – Jun 22 |
| Radishes | Sow outdoors (fall) | Jun 13 – Aug 14 |
| Kale | Sow outdoors (spring) | May 19 – Jun 8 |
| Kale | Sow outdoors (fall) | Jun 6 – Jul 14 |
| Carrots | Sow outdoors (spring) | Jun 2 – Jul 18 |
| Carrots | Sow outdoors (fall) | May 14 – Jun 29 |
| Garlic | Plant outdoors (fall) | Sep 13 – Oct 14 |
Where these dates come from
ZIP code 81623 is matched to the NOAA station Aspen 1Sw, CO, 32.4 km away, at 8,175 ft elevation (12 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Aspen 1Sw, CO (used) | 8,175 ft | Jun 2 | Sep 23 |
| Aspen Pitkin Co Ap, CO | 7,721 ft | May 31 | Sep 23 |
| Glenwood Spgs #2, CO | 5,895 ft | May 13 | Oct 3 |
| Shoshone, CO | 5,992 ft | May 1 | Oct 14 |
Frost dates near Carbondale
- Snowmass, CO 81654 · last —, first —
- Basalt, CO 81621 · last May 31, first Sep 23
- Snowmass Village, CO 81615 · last Jun 2, first Sep 23
- Woody Creek, CO 81656 · last May 31, first Sep 23
- Aspen, CO 81612 · last May 31, first Sep 23
- Glenwood Springs, CO 81601 · last May 13, first Oct 3
- Somerset, CO 81434 · last May 31, first Sep 23
- Crested Butte, CO 81225 · last —, first —
Frequently asked questions
- When is the last frost in Carbondale, CO?
- For ZIP code 81623, the average last spring frost (32°F) is June 2, based on NOAA 1991-2020 climate normals for the Aspen 1Sw, CO weather station. There is a 1-in-10 chance of a frost after June 17.
- When is the first frost in Carbondale, CO?
- The average first fall frost (32°F) is September 23. There is a 1-in-10 chance of frost by September 12, so tender plants are at risk from that point on.
- How long is the growing season in 81623?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 113 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.