New York frost dates: U
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Ulster Park | May 14 | Sep 28 | 137 d | 6a |
| Unadilla | May 11 | Oct 9 | 151 d | 5b |
| Union Hill | May 1 | Oct 20 | 172 d | 6b |
| Union Springs | May 1 | Oct 21 | 173 d | 6a |
| Uniondale | Apr 2 | Nov 12 | 224 d | 7b |
| Unionville | Apr 20 | Oct 20 | 183 d | 6b |
| Upper Jay | May 27 | Sep 22 | 118 d | 5a |
| Upton | Apr 21 | Oct 24 | 186 d | 7a |
| Utica | May 1 | Oct 13 | 165 d | 5b |