Frost dates for Content 4 NNE, MT
At Content 4 NNE, the median last spring frost (32°F) is May 25 and the median first fall frost is Sep 14, for a typical growing season of 110 days. For a 90% chance that the last frost has passed, wait until Jun 8. Nearby ZIP codes are in USDA hardiness zones 3b to 4b.
- May 25Last spring frost (median)50% chance of 32°F after this date
- Jun 8Safer planting date10% chance of 32°F after this date
- Sep 14First fall frost (median)50% chance of 32°F by this date
- 110 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 24 | Jun 7 | Jun 30 |
| 32°F | May 11 | May 25 | Jun 8 |
| 28°F | Apr 30 | May 14 | May 28 |
| 24°F | Apr 18 | May 3 | May 17 |
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 15 | Sep 2 | Sep 16 |
| 32°F | Aug 29 | Sep 14 | Sep 27 |
| 28°F | Sep 12 | Sep 24 | Oct 7 |
| 24°F | Sep 20 | Oct 3 | Oct 17 |
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 | 58 days | 85 days | 106 days |
| 32°F | 89 days | 110 days | 131 days |
| 28°F | 115 days | 133 days | 151 days |
| 24°F | 132 days | 152 days | 172 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 |
|---|---|---|---|
| 59538 | 4a | -30 to -25°F | 24 km |
| 59273 | 4a | -30 to -25°F | 50 km |
| 59261 | 3b | -35 to -30°F | 50 km |
| 59230 | 4a | -30 to -25°F | 54 km |
| 59241 | 3b | -35 to -30°F | 55 km |
| 59318 | 4b | -25 to -20°F | 64 km |
| 59524 | 4a | -30 to -25°F | 65 km |
| 59546 | 4b | -25 to -20°F | 78 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 USC00241984, at 48.0803, -107.5250, elevation 709 m (2,325 ft).
- Data quality: Standard (24+ years of data), 27 years of freeze data.
- Average days per year at or below 32°F: 183.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Malta 7 E (38 km)
- Malta (40 km)
- Hinsdale 4 SW (41 km)
- Malta 35 S (42 km)
- Saco 1 NNW (45 km)
- Glasgow #2 (67 km)
- Glasgow Intl Airport (69 km)
- Zortman (77 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.