Utah frost dates: B
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Bear River City | May 5 | Oct 5 | 153 d | 6b |
| Beaver | Jun 1 | Sep 28 | 119 d | 6a |
| Beryl | May 31 | Sep 20 | 112 d | 5b |
| Bicknell | May 31 | Sep 21 | 113 d | 6a |
| Bingham Canyon | Apr 18 | Oct 22 | 187 d | 7a |
| Blanding | Apr 28 | Oct 21 | 176 d | 7a |
| Bluebell | May 31 | Sep 23 | 115 d | 5b |
| Bluff | Apr 24 | Oct 13 | 172 d | 7a |
| Bonanza | May 12 | Oct 5 | 146 d | 6a |
| Boulder | May 4 | Oct 14 | 163 d | 7a |
| Bountiful | Apr 25 | Oct 24 | 182 d | 6b |
| Brian Head | Jun 21 | Sep 12 | 83 d | 6a |
| Brigham City | May 5 | Oct 5 | 153 d | 6b |
| Bryce | May 23 | Sep 27 | 127 d | 6a |