Frost dates for Grangeville, ID
At Grangeville, the median last spring frost (32°F) is May 9 and the median first fall frost is Oct 3, for a typical growing season of 146 days. For a 90% chance that the last frost has passed, wait until May 27. Nearby ZIP codes are in USDA hardiness zones 6b to 7a.
- May 9Last spring frost (median)50% chance of 32°F after this date
- May 27Safer planting date10% chance of 32°F after this date
- Oct 3First fall frost (median)50% chance of 32°F by this date
- 146 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 10 | May 28 | Jun 16 |
| 32°F | Apr 24 | May 9 | May 27 |
| 28°F | Apr 4 | Apr 22 | May 8 |
| 24°F | Mar 13 | Apr 2 | Apr 25 |
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 4 | Sep 19 | Oct 6 |
| 32°F | Sep 14 | Oct 3 | Oct 17 |
| 28°F | Sep 29 | Oct 15 | Nov 1 |
| 24°F | Oct 11 | Oct 29 | Nov 17 |
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 | 90 days | 112 days | 138 days |
| 32°F | 119 days | 146 days | 167 days |
| 28°F | 153 days | 176 days | 200 days |
| 24°F | 181 days | 209 days | 237 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 |
|---|---|---|---|
| 83530 | 6b | -5 to 0°F | 8 km |
| 83554 | 7a | 0 to 5°F | 31 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 USC00103771, at 45.9414, -116.1175, elevation 1006 m (3,300 ft).
- Data quality: Representative (10+ years), 22 years of freeze data.
- Average days per year at or below 32°F: 144.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Kooskia 5 SSE (20 km)
- Cottonwood 2 WSW (24 km)
- Kamiah (33 km)
- Nezperce (34 km)
- Lowell Three Rivers (46 km)
- Fenn Ranger Station (48 km)
- Winchester (51 km)
- Elk City 1ne (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.