Frost dates for Buffalo Johnson Co Airport, WY
At Buffalo Johnson Co Airport, the median last spring frost (32°F) is May 13 and the median first fall frost is Oct 1, for a typical growing season of 141 days. For a 90% chance that the last frost has passed, wait until May 28. Nearby ZIP codes are in USDA hardiness zones 4b to 5a.
- May 13Last 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
- 141 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 11 | May 26 | Jun 12 |
| 32°F | Apr 28 | May 13 | May 28 |
| 28°F | Apr 15 | Apr 30 | May 15 |
| 24°F | Apr 3 | Apr 17 | May 3 |
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 10 | Sep 23 | Oct 5 |
| 32°F | Sep 19 | Oct 1 | Oct 16 |
| 28°F | Sep 26 | Oct 10 | Oct 24 |
| 24°F | Oct 1 | Oct 19 | Nov 5 |
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 | 98 days | 118 days | 137 days |
| 32°F | 119 days | 141 days | 161 days |
| 28°F | 139 days | 163 days | 183 days |
| 24°F | 159 days | 183 days | 207 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
Closest ZIP codes (each is closer to another station)
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 82834 | 5a | -20 to -15°F | 13 km |
| 82832 | 5a | -20 to -15°F | 25 km |
| 82842 | 5a | -20 to -15°F | 27 km |
| 82845 | 5a | -20 to -15°F | 42 km |
| 82833 | 5a | -20 to -15°F | 43 km |
| 82835 | 5a | -20 to -15°F | 51 km |
| 82801 | 5a | -20 to -15°F | 52 km |
| 82837 | 4b | -25 to -20°F | 52 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 USW00094054, at 44.3814, -106.7211, elevation 1514 m (4,967 ft).
- Data quality: Representative (10+ years), 22 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
- Buffalo (3 km)
- Story (26 km)
- Billy Creek (29 km)
- Clearmont 5 SW (31 km)
- Big Horn (41 km)
- Sheridan Co Airport (47 km)
- Sheridan Field Station (52 km)
- Leiter 9n (62 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.