Frost dates for Aspen Pitkin Co Airport, CO
At Aspen Pitkin Co Airport, the median last spring frost (32°F) is May 31 and the median first fall frost is Sep 23, for a typical growing season of 114 days. For a 90% chance that the last frost has passed, wait until Jun 14. Nearby ZIP codes are in USDA hardiness zones 5b to 6a.
- May 31Last spring frost (median)50% chance of 32°F after this date
- Jun 14Safer planting date10% chance of 32°F after this date
- Sep 23First fall frost (median)50% chance of 32°F by this date
- 114 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | May 31 | Jun 12 | Jun 26 |
| 32°F | May 16 | May 31 | Jun 14 |
| 28°F | Apr 29 | May 13 | Jun 1 |
| 24°F | Apr 15 | Apr 30 | May 14 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Sep 1 | Sep 13 | Sep 24 |
| 32°F | Sep 11 | Sep 23 | Oct 3 |
| 28°F | Sep 21 | Oct 2 | Oct 14 |
| 24°F | Sep 29 | Oct 12 | Oct 24 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 74 days | 90 days | 107 days |
| 32°F | 94 days | 114 days | 133 days |
| 28°F | 119 days | 140 days | 159 days |
| 24°F | 144 days | 163 days | 182 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 81615 | 5b | -15 to -10°F | 7 km |
| 81656 | 5b | -15 to -10°F | 9 km |
| 81654 | 6a | -10 to -5°F | 15 km |
| 81623 | 6a | -10 to -5°F | 26 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USW00093073, at 39.2231, -106.8683, elevation 2353 m (7,720 ft).
- Data quality: Representative (10+ years), 21 years of freeze data.
- Average days per year at or below 32°F: 212.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Aspen 1sw (5 km)
- Meredith (19 km)
- Crested Butte (40 km)
- Sugarloaf Rsvr (43 km)
- Twin Lakes Rsvr (47 km)
- Leadville Lake Co Airport (48 km)
- Shoshone (49 km)
- Taylor Park (50 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.