Frost dates for 81602Glenwood Springs, CO
The average last spring frost in Glenwood Springs is May 13 and the average first fall frost is October 3, giving a typical growing season of about 142 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 13
- Average first fall frost
- Oct 3
- Growing season
- 142 days
Safer after May 30 (1-in-10 risk)
Possible by Sep 20 (1-in-10 risk)
Last frost typically in 193 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) | May 16 · May 30 · Jun 13 | Sep 10 · Sep 23 · Oct 4 | 115 days | 100% |
| Frost / freeze (32°F) | Apr 30 · May 13 · May 30 | Sep 20 · Oct 3 · Oct 15 | 142 days | 100% |
| Hard freeze (28°F) | Apr 14 · Apr 27 · May 11 | Sep 29 · Oct 14 · Oct 27 | 167 days | 100% |
Planting calendar for Glenwood Springs
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 | Apr 12 – Jun 18 |
| Tomatoes | Transplant outdoors | May 29 – Jun 13 |
| Peppers | Start seeds indoors | Apr 12 – May 13 |
| Peppers | Transplant outdoors | Jun 12 – Jul 13 |
| Eggplant | Start seeds indoors | Apr 29 – May 28 |
| Eggplant | Transplant outdoors | Jun 12 – Jul 13 |
| Cucumbers | Sow outdoors | Jun 12 – Jun 23 |
| Summer squash | Sow outdoors | May 29 – Jul 13 |
| Winter squash & pumpkins | Sow outdoors | Jun 12 – Jul 13 |
| Snap beans | Sow outdoors | May 29 – Jul 16 |
| Sweet corn | Sow outdoors | May 29 – Jun 13 |
| Watermelon & cantaloupe | Sow outdoors | Jun 12 – Jul 13 |
| Okra | Sow outdoors | Jun 5 – Jun 28 |
| Peas | Sow outdoors (spring) | Apr 12 – May 28 |
| Potatoes | Plant outdoors (spring) | Apr 12 – Jun 12 |
| Onions | Start seeds indoors (spring) | Mar 1 – Mar 28 |
| Onions | Transplant outdoors (spring) | Apr 29 – May 28 |
| Broccoli | Start seeds indoors (spring) | Mar 25 – Apr 28 |
| Broccoli | Transplant outdoors (spring) | Apr 29 – May 28 |
| Broccoli | Start seeds indoors (fall) | Jun 3 – Jun 13 |
| Broccoli | Transplant outdoors (fall) | Jul 3 – Jul 14 |
| Cabbage | Start seeds indoors (spring) | Mar 15 – Apr 12 |
| Cabbage | Transplant outdoors (spring) | Apr 12 – May 13 |
| Cabbage | Start seeds indoors (fall) | May 24 – Jun 23 |
| Cabbage | Transplant outdoors (fall) | Jun 23 – Jul 24 |
| Leaf lettuce | Sow outdoors (spring) | Apr 12 – Jun 28 |
| Leaf lettuce | Sow outdoors (fall) | Jun 23 – Aug 9 |
| Spinach | Sow outdoors (spring) | Apr 5 – May 19 |
| Spinach | Sow outdoors (fall) | Jul 10 – Aug 14 |
| Radishes | Sow outdoors (spring) | Apr 12 – Jun 2 |
| Radishes | Sow outdoors (fall) | Jun 23 – Aug 24 |
| Kale | Sow outdoors (spring) | Apr 29 – May 19 |
| Kale | Sow outdoors (fall) | Jun 16 – Jul 24 |
| Carrots | Sow outdoors (spring) | May 13 – Jun 28 |
| Carrots | Sow outdoors (fall) | May 24 – Jul 9 |
| Garlic | Plant outdoors (fall) | Sep 23 – Oct 24 |
Where these dates come from
ZIP code 81602 is matched to the NOAA station Glenwood Spgs #2, CO, 3.7 km away, at 5,895 ft elevation (134 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Glenwood Spgs #2, CO (used) | 5,895 ft | May 13 | Oct 3 |
| Shoshone, CO | 5,992 ft | May 1 | Oct 14 |
| Rifle 3Ene, CO | 5,469 ft | May 23 | Sep 25 |
| Rifle Garfield Co Ap, CO | 5,530 ft | May 11 | Oct 4 |
Frost dates near Glenwood Springs
- Glenwood Springs, CO 81601 · last May 13, first Oct 3
- New Castle, CO 81647 · last May 11, first Oct 4
- Silt, CO 81652 · last May 11, first Oct 4
- Gypsum, CO 81637 · last May 13, first Oct 3
- Carbondale, CO 81623 · last Jun 2, first Sep 23
- Basalt, CO 81621 · last May 31, first Sep 23
- Rifle, CO 81650 · last May 11, first Oct 4
- Snowmass, CO 81654 · last —, first —
Frequently asked questions
- When is the last frost in Glenwood Springs, CO?
- For ZIP code 81602, the average last spring frost (32°F) is May 13, based on NOAA 1991-2020 climate normals for the Glenwood Spgs #2, CO weather station. There is a 1-in-10 chance of a frost after May 30.
- When is the first frost in Glenwood Springs, CO?
- The average first fall frost (32°F) is October 3. There is a 1-in-10 chance of frost by September 20, so tender plants are at risk from that point on.
- How long is the growing season in 81602?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 142 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.