Frost dates for Utah Test Range, UT
At Utah Test Range, the median last spring frost (32°F) is May 15 and the median first fall frost is Oct 2, for a typical growing season of 139 days. For a 90% chance that the last frost has passed, wait until Jun 4. Nearby ZIP codes are in USDA hardiness zones 6b to 7b.
- May 15Last spring frost (median)50% chance of 32°F after this date
- Jun 4Safer planting date10% chance of 32°F after this date
- Oct 2First fall frost (median)50% chance of 32°F by this date
- 139 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 10 | May 30 | Jun 16 |
| 32°F | Apr 29 | May 15 | Jun 4 |
| 28°F | Apr 13 | Apr 30 | May 20 |
| 24°F | Mar 26 | Apr 15 | 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 |
|---|---|---|---|
| 36°F | Sep 10 | Sep 24 | Oct 6 |
| 32°F | Sep 19 | Oct 2 | Oct 16 |
| 28°F | Sep 28 | Oct 13 | Oct 26 |
| 24°F | Oct 7 | Oct 23 | Nov 5 |
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 | 94 days | 116 days | 137 days |
| 32°F | 115 days | 139 days | 161 days |
| 28°F | 140 days | 165 days | 186 days |
| 24°F | 163 days | 190 days | 215 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
Closest ZIP codes (each is closer to another station)
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 84029 | 7a | 0 to 5°F | 53 km |
| 84307 | 6b | -5 to 0°F | 58 km |
| 84315 | 7a | 0 to 5°F | 68 km |
| 84313 | 6b | -5 to 0°F | 72 km |
| 84083 | 6b | -5 to 0°F | 72 km |
| 84075 | 7b | 5 to 10°F | 73 km |
| 84404 | 7a | 0 to 5°F | 73 km |
| 84015 | 7a | 0 to 5°F | 74 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 USC00428978, at 41.0497, -112.9367, elevation 1353 m (4,440 ft).
- Data quality: Representative (10+ years), 25 years of freeze data.
- Average days per year at or below 32°F: 156.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Grantsville 2w (62 km)
- Brigham City 28 WNW (71 km)
- Garfield (72 km)
- Tooele (77 km)
- Ogden Sugar Factory (79 km)
- Ogden Hinkley Airport (79 km)
- Johnson Pass (84 km)
- Farmington 3 NW (84 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.