Frost dates for Fort Duchesne, UT
At Fort Duchesne, the median last spring frost (32°F) is May 19 and the median first fall frost is Oct 2, for a typical growing season of 135 days. For a 90% chance that the last frost has passed, wait until Jun 15. Nearby ZIP codes are in USDA hardiness zone 5b.
- May 19Last spring frost (median)50% chance of 32°F after this date
- Jun 15Safer planting date10% chance of 32°F after this date
- Oct 2First fall frost (median)50% chance of 32°F by this date
- 135 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 16 | Jun 3 | Jul 3 |
| 32°F | May 1 | May 19 | Jun 15 |
| 28°F | Apr 18 | May 3 | May 31 |
| 24°F | Apr 2 | Apr 19 | May 14 |
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 6 | Sep 22 | Oct 4 |
| 32°F | Sep 19 | Oct 2 | Oct 16 |
| 28°F | Sep 27 | Oct 12 | Oct 27 |
| 24°F | Oct 8 | Oct 25 | Nov 7 |
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 | 77 days | 110 days | 132 days |
| 32°F | 103 days | 135 days | 158 days |
| 28°F | 130 days | 161 days | 183 days |
| 24°F | 161 days | 187 days | 210 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 |
|---|---|---|---|
| 84026 | 5b | -15 to -10°F | 2 km |
| 84039 | 5b | -15 to -10°F | 18 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 USC00422996, at 40.2842, -109.8611, elevation 1540 m (5,052 ft).
- Data quality: Representative (10+ years), 20 years of freeze data.
- Average days per year at or below 32°F: 182.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Roosevelt Radio (8 km)
- Myton (20 km)
- Neola (22 km)
- Ouray 4ne (25 km)
- Vernal (33 km)
- Vernal Municipal Airport (34 km)
- Maeser 9nw (35 km)
- Altamont (38 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.