Ohio frost dates: U
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Uhrichsville | Apr 29 | Oct 15 | 169 d | 6b |
| Union City | Apr 20 | Oct 21 | 184 d | 6a |
| Union Furnace | Apr 30 | Oct 14 | 167 d | 6b |
| Uniontown | Apr 24 | Oct 26 | 185 d | 6b |
| Unionville | Apr 15 | Nov 9 | 208 d | 6b |
| Unionville Center | Apr 19 | Oct 26 | 190 d | 6a |
| Uniopolis | Apr 22 | Oct 22 | 183 d | 6a |
| Upper Sandusky | Apr 29 | Oct 17 | 171 d | 6a |
| Urbana | Apr 24 | Oct 19 | 178 d | 6a |
| Utica | Apr 29 | Oct 16 | 170 d | 6a |