Frost dates for Buffalo Bill Dam, WY
At Buffalo Bill Dam, the median last spring frost (32°F) is May 17 and the median first fall frost is Oct 3, for a typical growing season of 136 days. For a 90% chance that the last frost has passed, wait until Jun 3. Nearby ZIP codes are in USDA hardiness zones 4b to 5a.
- May 17Last spring frost (median)50% chance of 32°F after this date
- Jun 3Safer planting date10% chance of 32°F after this date
- Oct 3First fall frost (median)50% chance of 32°F by this date
- 136 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 15 | May 30 | Jun 16 |
| 32°F | May 1 | May 17 | Jun 3 |
| 28°F | Apr 19 | May 4 | May 25 |
| 24°F | Apr 4 | Apr 22 | May 8 |
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 4 | Sep 23 | Oct 5 |
| 32°F | Sep 18 | Oct 3 | Oct 17 |
| 28°F | Sep 29 | Oct 12 | Oct 27 |
| 24°F | Oct 5 | Oct 21 | Nov 9 |
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 | 85 days | 112 days | 135 days |
| 32°F | 113 days | 136 days | 157 days |
| 28°F | 134 days | 158 days | 180 days |
| 24°F | 157 days | 181 days | 206 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 |
|---|---|---|---|
| 82450 | 5a | -20 to -15°F | 21 km |
| 82440 | 5a | -20 to -15°F | 33 km |
| 82435 | 5a | -20 to -15°F | 36 km |
| 82414 | 5a | -20 to -15°F | 37 km |
| 82433 | 4b | -25 to -20°F | 50 km |
| 82411 | 5a | -20 to -15°F | 55 km |
| 82412 | 5a | -20 to -15°F | 58 km |
| 82421 | 5a | -20 to -15°F | 61 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 USC00481175, at 44.5075, -109.1675, elevation 1573 m (5,160 ft).
- Data quality: Representative (10+ years), 16 years of freeze data.
- Average days per year at or below 32°F: 140.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Cody (5 km)
- Wapiti 1wsw (20 km)
- Cody 12se (24 km)
- Cody 21 SW (26 km)
- Heart Mountain (28 km)
- Powell Field Station (44 km)
- Clark 3ne (48 km)
- Sunshine 3ne (51 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.