Frost dates for Sand Creek, MT
At Sand Creek, the median last spring frost (32°F) is May 12 and the median first fall frost is Sep 27, for a typical growing season of 136 days. For a 90% chance that the last frost has passed, wait until May 27. Nearby ZIP codes are in USDA hardiness zone 4b.
- May 12Last spring frost (median)50% chance of 32°F after this date
- May 27Safer planting date10% chance of 32°F after this date
- Sep 27First fall frost (median)50% chance of 32°F by this date
- 136 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 12 | May 24 | Jun 9 |
| 32°F | Apr 30 | May 12 | May 27 |
| 28°F | Apr 16 | May 1 | May 13 |
| 24°F | Apr 4 | Apr 19 | May 3 |
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 | Sep 5 | Sep 18 | Sep 27 |
| 32°F | Sep 14 | Sep 27 | Oct 8 |
| 28°F | Sep 22 | Oct 4 | Oct 17 |
| 24°F | Sep 29 | Oct 14 | Oct 27 |
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 | 96 days | 115 days | 131 days |
| 32°F | 118 days | 136 days | 154 days |
| 28°F | 137 days | 157 days | 176 days |
| 24°F | 154 days | 176 days | 196 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 |
|---|---|---|---|
| 59471 | 4b | -25 to -20°F | 17 km |
| 59489 | 4b | -25 to -20°F | 38 km |
| 59546 | 4b | -25 to -20°F | 38 km |
| 59527 | 4b | -25 to -20°F | 52 km |
| 59451 | 4b | -25 to -20°F | 54 km |
| 59535 | 4b | -25 to -20°F | 56 km |
| 59087 | 4b | -25 to -20°F | 61 km |
| 59032 | 4b | -25 to -20°F | 62 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 USC00247342, at 47.5775, -108.7283, elevation 887 m (2,910 ft).
- Data quality: Representative (10+ years), 13 years of freeze data.
- Average days per year at or below 32°F: 176.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Roy 8 NE (13 km)
- Valentine (32 km)
- Zortman (41 km)
- Winifred (49 km)
- Grass Range (62 km)
- Malta 35 S (65 km)
- Chinook 35se (69 km)
- Harlem 20s (74 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.