Frost dates for Fort Hall 1 NNE, ID
At Fort Hall 1 NNE, the median last spring frost (32°F) is May 20 and the median first fall frost is Sep 20, for a typical growing season of 119 days. For a 90% chance that the last frost has passed, wait until Jun 12. Nearby ZIP codes are in USDA hardiness zones 5b to 6a.
- May 20Last spring frost (median)50% chance of 32°F after this date
- Jun 12Safer planting date10% chance of 32°F after this date
- Sep 20First fall frost (median)50% chance of 32°F by this date
- 119 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 10 | Jun 27 |
| 32°F | May 6 | May 20 | Jun 12 |
| 28°F | Apr 23 | May 6 | May 23 |
| 24°F | Apr 8 | Apr 24 | 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 20 | Sep 7 | Sep 23 |
| 32°F | Sep 1 | Sep 20 | Oct 7 |
| 28°F | Sep 15 | Oct 4 | Oct 20 |
| 24°F | Sep 29 | Oct 17 | 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 | 61 days | 86 days | 110 days |
| 32°F | 91 days | 119 days | 142 days |
| 28°F | 122 days | 149 days | 170 days |
| 24°F | 153 days | 175 days | 197 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 |
|---|---|---|---|
| 83203 | 5b | -15 to -10°F | 2 km |
| 83202 | 6a | -10 to -5°F | 9 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 USC00103297, at 43.0425, -112.4144, elevation 1361 m (4,465 ft).
- Data quality: Standard (24+ years of data), 28 years of freeze data.
- Average days per year at or below 32°F: 186.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Pocatello 2 NE (17 km)
- Blackfoot Fire Dept (18 km)
- Pocatello Regional Airport (19 km)
- Pocatello City (19 km)
- Aberdeen Exp. Station (35 km)
- American Falls (42 km)
- American Falls 6 NE (43 km)
- McCammon (47 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.