Washington frost dates: A
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Aberdeen | Mar 29 | Nov 15 | 231 d | 8b |
| Acme | Mar 27 | Nov 6 | 224 d | 8a |
| Addy | May 16 | Sep 15 | 122 d | 6b |
| Adna | Apr 22 | Oct 27 | 188 d | 8b |
| Airway Heights | May 10 | Sep 26 | 139 d | 6b |
| Albion | May 6 | Sep 29 | 146 d | 7a |
| Allyn | Mar 24 | Nov 15 | 236 d | 8b |
| Almira | Jun 1 | Sep 22 | 113 d | 6b |
| Amanda Park | Apr 7 | Nov 10 | 217 d | 8b |
| Amboy | Apr 26 | Oct 16 | 173 d | 8b |
| Anacortes | Mar 8 | Nov 20 | 257 d | 8b |
| Anatone | Apr 6 | Oct 26 | 203 d | 7a |
| Anderson Island | Mar 11 | Nov 21 | 255 d | 8b |
| Appleton | May 12 | Oct 11 | 152 d | 7a |
| Ardenvoir | Apr 5 | Oct 24 | 202 d | 7a |
| Ariel | Apr 1 | Nov 18 | 231 d | 8b |
| Arlington | Apr 22 | Oct 19 | 180 d | 8b |
| Ashford | May 22 | Oct 3 | 134 d | 7a |
| Asotin | Apr 6 | Oct 26 | 203 d | 7a |
| Auburn | Mar 20 | Nov 10 | 235 d | 8b |