Frost dates for Wilsall 1s, MT
At Wilsall 1s, the median last spring frost (32°F) is Jun 4 and the median first fall frost is Sep 6, for a typical growing season of 92 days. For a 90% chance that the last frost has passed, wait until Jun 23. Nearby ZIP codes are in USDA hardiness zones 4b to 5a.
- Jun 4Last spring frost (median)50% chance of 32°F after this date
- Jun 23Safer planting date10% chance of 32°F after this date
- Sep 6First fall frost (median)50% chance of 32°F by this date
- 92 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 | Jun 6 | Jun 21 | Jul 7 |
| 32°F | May 19 | Jun 4 | Jun 23 |
| 28°F | May 4 | May 16 | Jun 2 |
| 24°F | Apr 25 | May 4 | May 16 |
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 | Aug 19 | Sep 1 | Sep 9 |
| 32°F | Aug 28 | Sep 6 | Sep 15 |
| 28°F | Sep 3 | Sep 13 | Sep 23 |
| 24°F | Sep 11 | Sep 22 | Oct 8 |
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 | 49 days | 70 days | 86 days |
| 32°F | 73 days | 92 days | 111 days |
| 28°F | 97 days | 117 days | 135 days |
| 24°F | 123 days | 140 days | 157 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 |
|---|---|---|---|
| 59086 | 4b | -25 to -20°F | 8 km |
| 59018 | 5a | -20 to -15°F | 16 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 USC00241840, at 45.9883, -110.6550, elevation 1529 m (5,015 ft).
- Data quality: Estimated from nearby stations (2+ years), 2 years of freeze data.
- Average days per year at or below 32°F: 220.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Wilsall 8 ENE (12 km)
- Livingston Mission Field (36 km)
- Lennep 5 SW (42 km)
- Bozeman Gallatin Field (45 km)
- Bozeman Montana State Univ (47 km)
- Melville 4 W (48 km)
- Bozeman 6 W Exp. Farm (52 km)
- Livingston 12 S (55 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.