Frost dates for Leiter 9n, WY
At Leiter 9n, the median last spring frost (32°F) is May 14 and the median first fall frost is Sep 30, for a typical growing season of 137 days. For a 90% chance that the last frost has passed, wait until May 29. Nearby ZIP codes are in USDA hardiness zones 4b to 5a.
- May 14Last spring frost (median)50% chance of 32°F after this date
- May 29Safer planting date10% chance of 32°F after this date
- Sep 30First fall frost (median)50% chance of 32°F by this date
- 137 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 27 | Jun 11 |
| 32°F | Apr 30 | May 14 | May 29 |
| 28°F | Apr 18 | May 2 | May 16 |
| 24°F | Apr 3 | Apr 19 | May 4 |
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 20 | Oct 2 |
| 32°F | Sep 17 | Sep 30 | Oct 13 |
| 28°F | Sep 25 | Oct 8 | Oct 23 |
| 24°F | Oct 2 | Oct 17 | Nov 1 |
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 | 93 days | 115 days | 133 days |
| 32°F | 118 days | 137 days | 154 days |
| 28°F | 137 days | 157 days | 176 days |
| 24°F | 158 days | 179 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 |
|---|---|---|---|
| 82835 | 5a | -20 to -15°F | 12 km |
| 82837 | 4b | -25 to -20°F | 14 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 USC00485506, at 44.8500, -106.2889, elevation 1268 m (4,160 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 168.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Clearmont 5 SW (33 km)
- Sheridan Field Station (43 km)
- Echeta 2 NW (51 km)
- Sheridan Co Airport (54 km)
- Story (57 km)
- Big Horn (60 km)
- Buffalo Johnson Co Airport (62 km)
- Buffalo (64 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.