Frost dates for Buckhorn Mountain 1 E, CO
At Buckhorn Mountain 1 E, the median last spring frost (32°F) is May 21 and the median first fall frost is Sep 29, for a typical growing season of 128 days. For a 90% chance that the last frost has passed, wait until Jun 4. Nearby ZIP codes are in USDA hardiness zone 5b.
- May 21Last spring frost (median)50% chance of 32°F after this date
- Jun 4Safer planting date10% chance of 32°F after this date
- Sep 29First fall frost (median)50% chance of 32°F by this date
- 128 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 18 | Jun 1 | Jun 15 |
| 32°F | May 9 | May 21 | Jun 4 |
| 28°F | Apr 29 | May 11 | May 26 |
| 24°F | Apr 17 | May 1 | May 16 |
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 6 | Sep 21 | Oct 3 |
| 32°F | Sep 12 | Sep 29 | Oct 12 |
| 28°F | Sep 22 | Oct 6 | Oct 22 |
| 24°F | Oct 1 | Oct 15 | Nov 2 |
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 | 89 days | 110 days | 126 days |
| 32°F | 107 days | 128 days | 148 days |
| 28°F | 124 days | 146 days | 167 days |
| 24°F | 143 days | 166 days | 189 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 |
|---|---|---|---|
| 80538 | 5b | -15 to -10°F | 9 km |
| 80535 | 5b | -15 to -10°F | 16 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 USC00051060, at 40.6158, -105.2969, elevation 2256 m (7,400 ft).
- Data quality: Representative (10+ years), 21 years of freeze data.
- Average days per year at or below 32°F: 164.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Fort Collins (18 km)
- Waterdale (22 km)
- Fort Collins 4 E (24 km)
- Loveland 2n (27 km)
- Hourglass Rsvr (29 km)
- Estes Park 3 SSE (35 km)
- Rustic 9wsw (36 km)
- Virginia Dale 7 ENE (39 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.