The freeze-free growing season lengthened in 87% (172) of 198 U.S. cities analyzed since 1970.
These 172 cities saw their freeze-free season lengthen by 20 days on average.
Cities across the Northwest (+24 days) and Southwest (+20 days) have experienced the largest average change.
The first spring leaves and flowers are unfolding early in parts of the south including in Atlanta, Georgia and Charlotte, North Carolina.
Climate Central assessed temperature trends in 198 U.S. cities to see how the length of the freeze-free growing season has changed from 1970 through 2024 (see Methodology).
The freeze-free season lengthened in 87% (172) of the 198 cities analyzed since 1970.
These 172 cities saw their freeze-free season lengthen by 20 days on average.
In 70 cities, the time between the annual last and first freeze grew by at least three weeks.
The freeze-free growing season increased the most in: Reno, Nev. (96 more days); Las Cruces, N.M. (66 more days); Medford, Ore. (63 more days); and Tupelo, Miss. and Myrtle Beach, S.C. (both 52 more days).
Longest freeze-free seasons: South, Southeast, Ohio Valley, Northeast
Region
Average change in freeze-free season length, 1970-2024
Average freeze-free season length, 1970-2024
Northwest
+24 days
168 days
Southwest
+20 days
174 days
Southeast
+18 days
229 days
Northeast
+17 days
180 days
Upper Midwest
+16 days
158 days
Northern Rockies and Plains
+14 days
136 days
South
+14 days
231 days
Ohio Valley
+13 days
188 days
Freeze-free season now at least 10% longer in 70 U.S. cities