Frost dates in Utah
Across Utah, the typical last spring frost is around May 6 and the first fall frost around Oct 9. Your own dates depend on where you are in the state; find your county below.
Most of the state's last spring frosts fall between Apr 9 and Jun 3, and its first fall frosts between Sep 18 and Oct 31.
These are the dates with a 50% chance of a 32°F frost on or after (spring) or on or before (fall), so plan tender crops a week or two after the spring date and keep row cover handy. For dates at your exact ZIP code, use the zone and frost date lookup; for what to plant when, see the planting guide by frost date.
Hardiness zones in Utah: zone 4a, zone 5a, zone 5b, zone 6a, zone 6b, zone 7a, zone 7b, zone 8a, zone 8b
Frost dates by county in Utah
| County | Last spring frost | First fall frost | Growing season |
|---|---|---|---|
| Beaver | Jun 1 | Oct 2 | About 123 days |
| Box Elder | May 5 | Oct 12 | About 160 days |
| Cache | May 8 | Oct 5 | About 150 days |
| Carbon | May 3 | Oct 25 | About 175 days |
| Daggett | May 22 | Sep 29 | About 130 days |
| Davis | Apr 24 | Oct 19 | About 178 days |
| Duchesne | May 31 | Sep 23 | About 115 days |
| Emery | May 18 | Sep 27 | About 132 days |
| Garfield | May 23 | Sep 27 | About 127 days |
| Grand | Apr 27 | Oct 9 | About 165 days |
| Iron | May 31 | Sep 20 | About 112 days |
| Juab | May 10 | Oct 10 | About 153 days |
| Kane | May 15 | Oct 8 | About 146 days |
| Millard | May 4 | Oct 13 | About 162 days |
| Morgan | Jun 4 | Sep 24 | About 112 days |
| Piute | May 24 | Sep 27 | About 126 days |
| Rich | Jun 3 | Sep 25 | About 114 days |
| Salt Lake | Apr 18 | Oct 22 | About 187 days |
| San Juan | Apr 28 | Oct 21 | About 176 days |
| Sanpete | May 26 | Sep 25 | About 122 days |
| Sevier | May 22 | Sep 24 | About 125 days |
| Summit | Jun 5 | Sep 17 | About 104 days |
| Tooele | May 15 | Oct 5 | About 143 days |
| Uintah | May 19 | Oct 3 | About 137 days |
| Utah | Apr 25 | Oct 18 | About 176 days |
| Wasatch | May 31 | Sep 20 | About 112 days |
| Washington | Apr 9 | Nov 5 | About 210 days |
| Wayne | May 31 | Oct 3 | About 125 days |
| Weber | Apr 22 | Oct 22 | About 183 days |
Source: NOAA NCEI U.S. Climate Normals 1991–2020, 50% probability of 32°F, from the weather station nearest each ZIP code; each county shows the middle value across its ZIP codes. Hills, valleys and cities can run a week or more earlier or later.