Utah frost dates: W
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Wales | May 26 | Sep 25 | 122 d | 5b |
| Wallsburg | May 28 | Sep 23 | 118 d | 6a |
| Washington | Mar 14 | Nov 10 | 241 d | 8b |
| Wellington | May 27 | Sep 26 | 122 d | 6a |
| Wellsville | May 12 | Sep 28 | 139 d | 6a |
| Wendover | Apr 18 | Oct 23 | 188 d | 6b |
| West Jordan | Apr 18 | Oct 22 | 187 d | 7b |
| West Valley City | Apr 8 | Oct 31 | 206 d | 7b |
| Whiterocks | May 19 | Sep 29 | 133 d | 6a |
| Willard | May 5 | Oct 5 | 153 d | 7a |
| Woodruff | frost any month | 5a | ||
| Woods Cross | Apr 24 | Oct 19 | 178 d | 7b |