Washington frost dates: U
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Underwood | Apr 20 | Oct 13 | 176 d | 8a |
| Union | Mar 24 | Nov 15 | 236 d | 8b |
| Uniontown | Apr 6 | Oct 26 | 203 d | 7a |
| University Place | Mar 11 | Nov 21 | 255 d | 8b |
| Usk | May 12 | Sep 21 | 132 d | 6a |
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Underwood | Apr 20 | Oct 13 | 176 d | 8a |
| Union | Mar 24 | Nov 15 | 236 d | 8b |
| Uniontown | Apr 6 | Oct 26 | 203 d | 7a |
| University Place | Mar 11 | Nov 21 | 255 d | 8b |
| Usk | May 12 | Sep 21 | 132 d | 6a |