Frost dates for Lewiston Nez Perce Co Airport, ID
At Lewiston Nez Perce Co Airport, the median last spring frost (32°F) is Apr 6 and the median first fall frost is Oct 26, for a typical growing season of 200 days. For a 90% chance that the last frost has passed, wait until Apr 26. Nearby ZIP codes are in USDA hardiness zones 7a to 7b.
- Apr 6Last spring frost (median)50% chance of 32°F after this date
- Apr 26Safer planting date10% chance of 32°F after this date
- Oct 26First fall frost (median)50% chance of 32°F by this date
- 200 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 | Apr 11 | Apr 29 | May 12 |
| 32°F | Mar 20 | Apr 6 | Apr 26 |
| 28°F | Feb 25 | Mar 15 | Apr 4 |
| 24°F | Jan 27 | Feb 27 | Mar 19 |
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 | Oct 1 | Oct 13 | Oct 28 |
| 32°F | Oct 10 | Oct 26 | Nov 12 |
| 28°F | Oct 20 | Nov 8 | Nov 28 |
| 24°F | Oct 30 | Nov 23 | Dec 13 |
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 | 150 days | 170 days | 189 days |
| 32°F | 176 days | 200 days | 225 days |
| 28°F | 209 days | 235 days | 265 days |
| 24°F | 240 days | 271 days | 305 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 |
|---|---|---|---|
| 83501 | 7b | 5 to 10°F | 15 km |
| 99179 | 7a | 0 to 5°F | 16 km |
| 99403 | 7b | 5 to 10°F | 21 km |
| 99402 | 7a | 0 to 5°F | 31 km |
| 99401 | 7a | 0 to 5°F | 37 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 USW00024149, at 46.3747, -117.0156, elevation 438 m (1,436 ft).
- Data quality: Standard (24+ years of data), 28 years of freeze data.
- Average days per year at or below 32°F: 80.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Winchester (34 km)
- Moscow U Of I (40 km)
- Dworshak Fish Hatchery (55 km)
- Cottonwood 2 WSW (61 km)
- Nezperce (61 km)
- Potlatch 3 NNE (66 km)
- Kamiah (77 km)
- Elk River (78 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.