Missouri frost dates: U
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Udall | Apr 9 | Oct 23 | 197 d | 7a |
| Ulman | Apr 8 | Oct 28 | 203 d | 6b |
| Union | Apr 11 | Oct 23 | 195 d | 6b |
| Union Star | Apr 17 | Oct 19 | 185 d | 6a |
| Uniontown | Apr 19 | Oct 20 | 184 d | 7a |
| Unionville | Apr 17 | Oct 22 | 188 d | 5b |
| Urbana | Apr 7 | Oct 28 | 204 d | 6b |
| Urich | Apr 17 | Oct 21 | 187 d | 6b |
| Utica | Apr 15 | Oct 21 | 189 d | 6a |