Frost dates for Fossil, OR
At Fossil, the median last spring frost (32°F) is Jun 3 and the median first fall frost is Sep 14, for a typical growing season of 98 days. For a 90% chance that the last frost has passed, wait until Jul 3. Nearby ZIP codes are in USDA hardiness zone 7a.
- Jun 3Last spring frost (median)50% chance of 32°F after this date
- Jul 3Safer planting date10% chance of 32°F after this date
- Sep 14First fall frost (median)50% chance of 32°F by this date
- 98 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 13 | Jun 3 | Jul 3 |
| 28°F | Apr 24 | May 10 | Jun 1 |
| 24°F | Mar 31 | Apr 24 | May 10 |
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 | Aug 25 | Sep 14 | Oct 3 |
| 28°F | Sep 10 | Oct 2 | Oct 23 |
| 24°F | Sep 29 | Oct 17 | Nov 8 |
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 | 29 days | 54 days | 83 days |
| 32°F | 64 days | 98 days | 129 days |
| 28°F | 113 days | 142 days | 168 days |
| 24°F | 148 days | 177 days | 205 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 |
|---|---|---|---|
| 97830 | 7a | 0 to 5°F | 4 km |
| 97750 | 7a | 0 to 5°F | 19 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 USC00353038, at 44.9983, -120.2175, elevation 808 m (2,650 ft).
- Data quality: Representative (10+ years), 22 years of freeze data.
- Average days per year at or below 32°F: 127.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Condon (27 km)
- Kent (44 km)
- Antelope 6 SSW (47 km)
- Mitchell 2 E (49 km)
- Heppner (65 km)
- Monument 2 (66 km)
- John Day 35 WNW (67 km)
- Dayville 8 NW (67 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.