Frost dates for Divide, MT
At Divide, the median last spring frost (32°F) is Jun 10 and the median first fall frost is Sep 7, for a typical growing season of 85 days. For a 90% chance that the last frost has passed, wait until Jul 2. Nearby ZIP codes are in USDA hardiness zone 5a.
- Jun 10Last spring frost (median)50% chance of 32°F after this date
- Jul 2Safer planting date10% chance of 32°F after this date
- Sep 7First fall frost (median)50% chance of 32°F by this date
- 85 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 10 | Jul 2 |
| 28°F | May 6 | May 21 | Jun 9 |
| 24°F | Apr 22 | May 7 | May 21 |
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 24 | Sep 7 | Sep 20 |
| 28°F | Sep 3 | Sep 19 | Oct 2 |
| 24°F | Sep 14 | Oct 1 | Oct 16 |
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 | 30 days | 52 days | 75 days |
| 32°F | 59 days | 85 days | 108 days |
| 28°F | 96 days | 119 days | 137 days |
| 24°F | 124 days | 146 days | 165 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 |
|---|---|---|---|
| 59727 | 5a | -20 to -15°F | 8 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 USC00242421, at 45.7511, -112.7547, elevation 1631 m (5,350 ft).
- Data quality: Representative (10+ years), 18 years of freeze data.
- Average days per year at or below 32°F: 223.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Wise River 3 WNW (19 km)
- Glen 4 N (25 km)
- Butte Bert Mooney Airport (31 km)
- Twin Bridges (40 km)
- Anaconda (44 km)
- Wisdom (56 km)
- Dillon Airport (57 km)
- Dillon U Of Montana Western (61 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.