Frost dates for Cascade 1 NW, ID
At Cascade 1 NW, the median last spring frost (32°F) is May 30 and the median first fall frost is Sep 19, for a typical growing season of 110 days. For a 90% chance that the last frost has passed, wait until Jun 21. Nearby ZIP codes are in USDA hardiness zone 5a.
- May 30Last spring frost (median)50% chance of 32°F after this date
- Jun 21Safer planting date10% chance of 32°F after this date
- Sep 19First fall frost (median)50% chance of 32°F by this date
- 110 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 10 | May 30 | Jun 21 |
| 28°F | Apr 21 | May 6 | May 28 |
| 24°F | Apr 4 | Apr 19 | May 6 |
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 | Sep 3 | Sep 19 | Oct 4 |
| 28°F | Sep 15 | Oct 2 | Oct 18 |
| 24°F | Sep 30 | Oct 16 | Nov 3 |
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 | 53 days | 76 days | 99 days |
| 32°F | 81 days | 110 days | 136 days |
| 28°F | 120 days | 147 days | 170 days |
| 24°F | 154 days | 178 days | 201 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 |
|---|---|---|---|
| 83615 | 5a | -20 to -15°F | 20 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 USC00101514, at 44.5228, -116.0481, elevation 1492 m (4,896 ft).
- Data quality: Representative (10+ years), 23 years of freeze data.
- Average days per year at or below 32°F: 225.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Deadwood Lodge (38 km)
- Council (39 km)
- McCall (41 km)
- McCall Airport (41 km)
- Ola (43 km)
- Garden Valley (47 km)
- Cambridge (50 km)
- New Meadows Ranger Station (54 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.