Frost dates for Bern, ID
At Bern, the median last spring frost (32°F) is Jun 17 and the median first fall frost is Sep 3, for a typical growing season of 77 days. For a 90% chance that the last frost has passed, wait until Jul 4. Nearby ZIP codes are in USDA hardiness zones 5a to 6a.
- Jun 17Last spring frost (median)50% chance of 32°F after this date
- Jul 4Safer planting date10% chance of 32°F after this date
- Sep 3First fall frost (median)50% chance of 32°F by this date
- 77 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 31 | Jun 17 | Jul 4 |
| 28°F | May 9 | May 25 | Jun 17 |
| 24°F | Apr 23 | May 7 | May 26 |
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 18 | Sep 3 | Sep 18 |
| 28°F | Sep 1 | Sep 16 | Oct 1 |
| 24°F | Sep 10 | Sep 29 | Oct 15 |
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 | 29 days | 50 days | 70 days |
| 32°F | 53 days | 77 days | 102 days |
| 28°F | 84 days | 111 days | 135 days |
| 24°F | 118 days | 142 days | 164 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 |
|---|---|---|---|
| 83220 | 5a | -20 to -15°F | 1 km |
| 83254 | 5a | -20 to -15°F | 12 km |
| 83261 | 5a | -20 to -15°F | 13 km |
| 83239 | 5b | -15 to -10°F | 22 km |
| 83283 | 6a | -10 to -5°F | 23 km |
| 83238 | 5b | -15 to -10°F | 24 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 USC00100803, at 42.3353, -111.3850, elevation 1818 m (5,964 ft).
- Data quality: Standard (24+ years of data), 27 years of freeze data.
- Average days per year at or below 32°F: 217.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Lifton Pumping Station (24 km)
- Soda Springs Airport (39 km)
- Grace (40 km)
- Preston (49 km)
- Lava Hot Springs (60 km)
- Downey (62 km)
- McCammon (75 km)
- Malad City (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.