Frost dates for Tooele, UT
At Tooele, the median last spring frost (32°F) is May 2 and the median first fall frost is Oct 16, for a typical growing season of 165 days. For a 90% chance that the last frost has passed, wait until May 28. Nearby ZIP codes are in USDA hardiness zone 7a.
- May 2Last spring frost (median)50% chance of 32°F after this date
- May 28Safer planting date10% chance of 32°F after this date
- Oct 16First fall frost (median)50% chance of 32°F by this date
- 165 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 | Apr 29 | May 16 | Jun 6 |
| 32°F | Apr 16 | May 2 | May 28 |
| 28°F | Mar 29 | Apr 16 | May 7 |
| 24°F | Mar 4 | Mar 26 | Apr 15 |
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 23 | Oct 6 | Oct 19 |
| 32°F | Oct 2 | Oct 16 | Nov 2 |
| 28°F | Oct 13 | Oct 27 | Nov 12 |
| 24°F | Oct 22 | Nov 8 | Nov 22 |
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 | 114 days | 141 days | 165 days |
| 32°F | 138 days | 165 days | 190 days |
| 28°F | 165 days | 193 days | 218 days |
| 24°F | 199 days | 225 days | 252 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 |
|---|---|---|---|
| 84074 | 7a | 0 to 5°F | 5 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 USC00428771, at 40.5353, -112.3217, elevation 1507 m (4,944 ft).
- Data quality: Representative (10+ years), 23 years of freeze data.
- Average days per year at or below 32°F: 128.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Grantsville 2w (17 km)
- Garfield (23 km)
- Johnson Pass (33 km)
- Draper-Point Of Mountain (36 km)
- Fairfield (36 km)
- Salt Lake City Intl Airport (40 km)
- Utah Lake Lehi (41 km)
- Salt Lake Triad Center (44 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.