Frost dates for 80510Allenspark, CO
The average last spring frost in Allenspark is June 14 and the average first fall frost is September 12, giving a typical growing season of about 92 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Jun 14
- Average first fall frost
- Sep 12
- Growing season
- 92 days
Safer after Jun 28 (1-in-10 risk)
Possible by Aug 25 (1-in-10 risk)
Last frost typically in 230 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) | — | — | 58 days | 100% |
| Frost / freeze (32°F) | May 24 · Jun 14 · Jun 28 | Aug 25 · Sep 12 · Sep 25 | 92 days | 100% |
| Hard freeze (28°F) | May 7 · May 27 · Jun 15 | Sep 11 · Sep 25 · Oct 8 | 120 days | 100% |
Planting calendar for Allenspark
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 14 – Jul 20 |
| Tomatoes | Transplant outdoors | Jun 30 – May 23 |
| Peppers | Start seeds indoors | May 14 – Jun 14 |
| Peppers | Transplant outdoors | Jul 14 – Aug 14 |
| Eggplant | Start seeds indoors | May 31 – Jun 29 |
| Eggplant | Transplant outdoors | Jul 14 – Aug 14 |
| Cucumbers | Sow outdoors | Jul 14 – Jun 2 |
| Summer squash | Sow outdoors | Jun 30 – Aug 14 |
| Winter squash & pumpkins | Sow outdoors | Jul 14 – Aug 14 |
| Snap beans | Sow outdoors | Jun 30 – Jun 25 |
| Sweet corn | Sow outdoors | Jun 30 – May 23 |
| Watermelon & cantaloupe | Sow outdoors | Jul 14 – Aug 14 |
| Okra | Sow outdoors | Jul 7 – Jul 30 |
| Peas | Sow outdoors (spring) | May 14 – Jun 29 |
| Potatoes | Plant outdoors (spring) | May 14 – Jul 14 |
| Onions | Start seeds indoors (spring) | Apr 2 – Apr 29 |
| Onions | Transplant outdoors (spring) | May 31 – Jun 29 |
| Broccoli | Start seeds indoors (spring) | Apr 26 – May 30 |
| Broccoli | Transplant outdoors (spring) | May 31 – Jun 29 |
| Broccoli | Start seeds indoors (fall) | May 13 – May 23 |
| Broccoli | Transplant outdoors (fall) | Jun 12 – Jun 23 |
| Cabbage | Start seeds indoors (spring) | Apr 16 – May 14 |
| Cabbage | Transplant outdoors (spring) | May 14 – Jun 14 |
| Cabbage | Start seeds indoors (fall) | May 3 – Jun 2 |
| Cabbage | Transplant outdoors (fall) | Jun 2 – Jul 3 |
| Leaf lettuce | Sow outdoors (spring) | May 14 – Jul 30 |
| Leaf lettuce | Sow outdoors (fall) | Jun 2 – Jul 19 |
| Spinach | Sow outdoors (spring) | May 7 – Jun 20 |
| Spinach | Sow outdoors (fall) | Jun 19 – Jul 24 |
| Radishes | Sow outdoors (spring) | May 14 – Jul 4 |
| Radishes | Sow outdoors (fall) | Jun 2 – Aug 3 |
| Kale | Sow outdoors (spring) | May 31 – Jun 20 |
| Kale | Sow outdoors (fall) | May 26 – Jul 3 |
| Carrots | Sow outdoors (spring) | Jun 14 – Jul 30 |
| Carrots | Sow outdoors (fall) | May 3 – Jun 18 |
| Garlic | Plant outdoors (fall) | Sep 2 – Oct 3 |
Where these dates come from
ZIP code 80510 is matched to the NOAA station Allenspark 3Nw, CO, 0.3 km away, at 8,500 ft elevation (81 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Allenspark 3Nw, CO (used) | 8,500 ft | Jun 14 | Sep 12 |
| Estes Park 3 Sse, CO | 7,812 ft | May 30 | Sep 17 |
| Boulder 14 W, CO | 9,829 ft | Jun 21 | Sep 2 |
| Grand Lake 1 Nw, CO | 8,721 ft | — | — |
Frost dates near Allenspark
- Estes Park, CO 80517 · last May 30, first Sep 17
- Jamestown, CO 80455 · last May 24, first Sep 23
- Lyons, CO 80540 · last May 6, first Oct 5
- Ward, CO 80481 · last Jun 5, first Sep 16
- Boulder, CO 80306 · last May 24, first Sep 23
- Hygiene, CO 80533 · last May 7, first Oct 5
- Drake, CO 80515 · last May 30, first Sep 17
- Glen Haven, CO 80532 · last May 30, first Sep 17
Frequently asked questions
- When is the last frost in Allenspark, CO?
- For ZIP code 80510, the average last spring frost (32°F) is June 14, based on NOAA 1991-2020 climate normals for the Allenspark 3Nw, CO weather station. There is a 1-in-10 chance of a frost after June 28.
- When is the first frost in Allenspark, CO?
- The average first fall frost (32°F) is September 12. There is a 1-in-10 chance of frost by August 25, so tender plants are at risk from that point on.
- How long is the growing season in 80510?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 92 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.