Frost dates for Bonners Ferry, ID
At Bonners Ferry, the median last spring frost (32°F) is Apr 30 and the median first fall frost is Oct 4, for a typical growing season of 154 days. For a 90% chance that the last frost has passed, wait until May 16. Nearby ZIP codes are in USDA hardiness zone 6b.
- Apr 30Last spring frost (median)50% chance of 32°F after this date
- May 16Safer planting date10% chance of 32°F after this date
- Oct 4First fall frost (median)50% chance of 32°F by this date
- 154 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 1 | May 18 | Jun 8 |
| 32°F | Apr 16 | Apr 30 | May 16 |
| 28°F | Mar 26 | Apr 10 | Apr 30 |
| 24°F | Mar 3 | Mar 20 | Apr 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 |
|---|---|---|---|
| 36°F | Sep 5 | Sep 22 | Oct 6 |
| 32°F | Sep 18 | Oct 4 | Oct 19 |
| 28°F | Sep 28 | Oct 16 | Nov 5 |
| 24°F | Oct 6 | Oct 30 | Nov 23 |
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 | 96 days | 124 days | 146 days |
| 32°F | 132 days | 154 days | 174 days |
| 28°F | 160 days | 186 days | 211 days |
| 24°F | 194 days | 221 days | 248 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 |
|---|---|---|---|
| 83847 | 6b | -5 to 0°F | 15 km |
| 83845 | 6b | -5 to 0°F | 17 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 USC00101079, at 48.6928, -116.3103, elevation 632 m (2,075 ft).
- Data quality: Standard (24+ years of data), 28 years of freeze data.
- Average days per year at or below 32°F: 147.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Porthill 1 SW (36 km)
- Sandpoint Exp. Station (48 km)
- Priest River Exp. Station (54 km)
- Cabinet Gorge (70 km)
- Bayview Model Basin (81 km)
- Coeur D'alene (118 km)
- Prichard 3 ESE (120 km)
- Kellogg (130 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.