Indiana frost dates: U
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Underwood | Apr 18 | Oct 20 | 185 d | 6b |
| Union City | Apr 20 | Oct 21 | 184 d | 6a |
| Union Mills | Apr 29 | Oct 13 | 167 d | 5b |
| Uniondale | Apr 24 | Oct 20 | 179 d | 6a |
| Unionville | Apr 15 | Oct 26 | 194 d | 6b |
| Universal | Apr 15 | Oct 19 | 187 d | 6a |
| Upland | Apr 22 | Oct 22 | 183 d | 6a |
| Urbana | Apr 26 | Oct 19 | 176 d | 6a |