Frost dates for Mullan Pass Vor/dme, ID
At Mullan Pass Vor/dme, the median last spring frost (32°F) is Jun 10 and the median first fall frost is Sep 23, for a typical growing season of 104 days. For a 90% chance that the last frost has passed, wait until Jun 25. Nearby ZIP codes are in USDA hardiness zone 6a.
- Jun 10Last spring frost (median)50% chance of 32°F after this date
- Jun 25Safer planting date10% chance of 32°F after this date
- Sep 23First fall frost (median)50% chance of 32°F by this date
- 104 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 21 | Jun 10 | Jun 25 |
| 28°F | May 1 | May 21 | Jun 12 |
| 24°F | Apr 17 | May 2 | May 23 |
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 4 | Sep 23 | Oct 8 |
| 28°F | Sep 17 | Oct 5 | Oct 21 |
| 24°F | Sep 29 | Oct 19 | Nov 4 |
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 | 51 days | 77 days | 101 days |
| 32°F | 78 days | 104 days | 130 days |
| 28°F | 107 days | 135 days | 161 days |
| 24°F | 140 days | 169 days | 190 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 |
|---|---|---|---|
| 59867 | 6a | -10 to -5°F | 10 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 USW00024154, at 47.4569, -115.6450, elevation 1837 m (6,028 ft).
- Data quality: Representative (10+ years), 24 years of freeze data.
- Average days per year at or below 32°F: 206.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Mullan (13 km)
- Wallace (22 km)
- Prichard 3 ESE (29 km)
- Kellogg (37 km)
- Saint Maries (72 km)
- Cabinet Gorge (76 km)
- Elk River (85 km)
- Bayview Model Basin (90 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.