Washington frost dates: H
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Hamilton | Mar 28 | Nov 14 | 231 d | 8b |
| Hansville | Mar 9 | Nov 17 | 253 d | 8b |
| Harrah | Apr 21 | Oct 15 | 177 d | 7a |
| Harrington | May 31 | Sep 12 | 104 d | 6b |
| Hartline | May 2 | Oct 12 | 163 d | 6b |
| Hay | May 13 | Sep 26 | 136 d | 7a |
| Heisson | Apr 26 | Oct 16 | 173 d | 8b |
| Hobart | Apr 20 | Oct 25 | 188 d | 8b |
| Hoodsport | Mar 24 | Nov 15 | 236 d | 8b |
| Hooper | May 13 | Sep 26 | 136 d | 7a |
| Hoquiam | Mar 30 | Nov 14 | 229 d | 8b |
| Humptulips | Apr 26 | Oct 22 | 179 d | 8b |
| Hunters | May 16 | Sep 15 | 122 d | 6b |
| Husum | May 12 | Oct 11 | 152 d | 8a |