Frost dates for Wilsall 8 ENE, MT
At Wilsall 8 ENE, the median last spring frost (32°F) is Jun 8 and the median first fall frost is Sep 7, for a typical growing season of 89 days. For a 90% chance that the last frost has passed, wait until Jun 30. Nearby ZIP codes are in USDA hardiness zones 4b to 5a.
- Jun 8Last spring frost (median)50% chance of 32°F after this date
- Jun 30Safer planting date10% chance of 32°F after this date
- Sep 7First fall frost (median)50% chance of 32°F by this date
- 89 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 |
|---|---|---|---|
| 32°F | May 23 | Jun 8 | Jun 30 |
| 28°F | May 7 | May 20 | Jun 4 |
| 24°F | Apr 23 | May 6 | May 20 |
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 |
|---|---|---|---|
| 32°F | Aug 21 | Sep 7 | Sep 22 |
| 28°F | Sep 6 | Sep 23 | Oct 7 |
| 24°F | Sep 21 | Oct 4 | Oct 21 |
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 | 34 days | 56 days | 79 days |
| 32°F | 63 days | 89 days | 111 days |
| 28°F | 101 days | 124 days | 143 days |
| 24°F | 131 days | 150 days | 171 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 |
|---|---|---|---|
| 59086 | 4b | -25 to -20°F | 13 km |
| 59018 | 5a | -20 to -15°F | 22 km |
| 59082 | 5a | -20 to -15°F | 26 km |
| 59642 | 4b | -25 to -20°F | 33 km |
| 59085 | 4b | -25 to -20°F | 41 km |
| 59011 | 5a | -20 to -15°F | 45 km |
| 59053 | 4b | -25 to -20°F | 46 km |
| 59715 | 5a | -20 to -15°F | 49 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 USC00249023, at 46.0306, -110.5056, elevation 1788 m (5,865 ft).
- Data quality: Representative (10+ years), 22 years of freeze data.
- Average days per year at or below 32°F: 205.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Wilsall 1s (12 km)
- Melville 4 W (36 km)
- Livingston Mission Field (37 km)
- Lennep 5 SW (37 km)
- Big Timber (48 km)
- Martinsdale 3 NNW (54 km)
- Bozeman Gallatin Field (57 km)
- Bozeman Montana State Univ (59 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.