Frost dates for Saint Anthony, ID
At Saint Anthony, the median last spring frost (32°F) is May 17 and the median first fall frost is Sep 22, for a typical growing season of 126 days. For a 90% chance that the last frost has passed, wait until Jun 10. Nearby ZIP codes are in USDA hardiness zone 5a.
- May 17Last spring frost (median)50% chance of 32°F after this date
- Jun 10Safer planting date10% chance of 32°F after this date
- Sep 22First fall frost (median)50% chance of 32°F by this date
- 126 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 21 | Jun 8 | Jun 30 |
| 32°F | May 4 | May 17 | Jun 10 |
| 28°F | Apr 21 | May 4 | May 17 |
| 24°F | Apr 5 | Apr 22 | May 7 |
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 26 | Sep 10 | Sep 25 |
| 32°F | Sep 5 | Sep 22 | Oct 7 |
| 28°F | Sep 17 | Oct 4 | Oct 20 |
| 24°F | Sep 28 | Oct 15 | Nov 1 |
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 | 67 days | 93 days | 118 days |
| 32°F | 99 days | 126 days | 148 days |
| 28°F | 131 days | 152 days | 172 days |
| 24°F | 152 days | 175 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% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 83438 | 5a | -20 to -15°F | 6 km |
| 83445 | 5a | -20 to -15°F | 11 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 USC00108022, at 43.9517, -111.6789, elevation 1497 m (4,910 ft).
- Data quality: Representative (10+ years), 22 years of freeze data.
- Average days per year at or below 32°F: 206.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Sugar City (9 km)
- Rexburg Madison Co Airport (17 km)
- Rexburg Byu Idaho (18 km)
- Ashton 1n (22 km)
- Tetonia Exp. Station (34 km)
- Rigby (36 km)
- Hamer 4 NW (47 km)
- Driggs (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.