In Utah, the average number of days between the last spring freeze and the first freeze in the fall ranges from 56 at Woodruff, Rich County, to 216 at St. George. (In Woodruff, July typically is the only month with no temperatures below 32 degrees.)
AVERAGE LENGTH OF LONGEST FREEZE-FREE PERIOD, IN DAYS
St. George 216
Tremonton 189
Moab 181
Salt Lake City 173
Ogden 161
Cedar City 135
Heber 84
Woodruff 56
SOURCE: Utah Climate Center at USU