Frost dates for Raynesford 2 NNW, MT
At Raynesford 2 NNW, the median last spring frost (32°F) is May 22 and the median first fall frost is Sep 23, for a typical growing season of 123 days. For a 90% chance that the last frost has passed, wait until Jun 9. Nearby ZIP codes are in USDA hardiness zone 4b.
- May 22Last spring frost (median)50% chance of 32°F after this date
- Jun 9Safer planting date10% chance of 32°F after this date
- Sep 23First fall frost (median)50% chance of 32°F by this date
- 123 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 23 | Jun 9 | Jul 3 |
| 32°F | May 7 | May 22 | Jun 9 |
| 28°F | Apr 23 | May 7 | May 22 |
| 24°F | Apr 7 | Apr 27 | May 11 |
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 27 | Sep 12 | Sep 25 |
| 32°F | Sep 7 | Sep 23 | Oct 6 |
| 28°F | Sep 20 | Oct 2 | Oct 18 |
| 24°F | Sep 27 | Oct 11 | Oct 29 |
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 | 63 days | 92 days | 114 days |
| 32°F | 99 days | 123 days | 144 days |
| 28°F | 128 days | 147 days | 169 days |
| 24°F | 146 days | 168 days | 193 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 |
|---|---|---|---|
| 59412 | 4b | -25 to -20°F | 9 km |
| 59469 | 4b | -25 to -20°F | 13 km |
| 59447 | 4b | -25 to -20°F | 22 km |
| 59480 | 4b | -25 to -20°F | 27 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 USC00246902, at 47.2972, -110.7456, elevation 1285 m (4,215 ft).
- Data quality: Representative (10+ years), 22 years of freeze data.
- Average days per year at or below 32°F: 165.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Neihart 8 NNW (29 km)
- Shonkin 7 S (29 km)
- Highwood 7 NE (39 km)
- Stanford (42 km)
- Great Falls 16st (45 km)
- Geraldine (49 km)
- Great Falls WFO (51 km)
- Great Falls Intl Airport (52 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.