Frost dates for Cheyenne WFO, WY
At Cheyenne WFO, the median last spring frost (32°F) is May 14 and the median first fall frost is Oct 1, for a typical growing season of 139 days. For a 90% chance that the last frost has passed, wait until May 28. Nearby ZIP codes are in USDA hardiness zone 5b.
- May 14Last spring frost (median)50% chance of 32°F after this date
- May 28Safer planting date10% chance of 32°F after this date
- Oct 1First fall frost (median)50% chance of 32°F by this date
- 139 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 13 | May 26 | Jun 7 |
| 32°F | May 3 | May 14 | May 28 |
| 28°F | Apr 20 | May 3 | May 17 |
| 24°F | Apr 8 | Apr 23 | May 7 |
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 11 | Sep 24 | Oct 5 |
| 32°F | Sep 17 | Oct 1 | Oct 14 |
| 28°F | Sep 27 | Oct 10 | Oct 23 |
| 24°F | Oct 4 | Oct 19 | Nov 3 |
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 | 101 days | 120 days | 136 days |
| 32°F | 119 days | 139 days | 155 days |
| 28°F | 137 days | 157 days | 175 days |
| 24°F | 156 days | 176 days | 199 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 |
|---|---|---|---|
| 82005 | 5b | -15 to -10°F | 5 km |
| 82001 | 5b | -15 to -10°F | 11 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 USC00481676, at 41.1517, -104.8061, elevation 1865 m (6,119 ft).
- Data quality: Representative (10+ years), 18 years of freeze data.
- Average days per year at or below 32°F: 169.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Cheyenne (0 km)
- Archer (12 km)
- Hecla 1e (30 km)
- Carpenter 3n (37 km)
- Pine Bluffs 5w (54 km)
- Phillips (59 km)
- Laramie 4se (62 km)
- Pine Bluffs 1ese (63 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.