Washington frost dates: W
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Wahkiacus | May 12 | Oct 11 | 152 d | 7b |
| Waitsburg | Apr 28 | Oct 13 | 168 d | 7a |
| Waldron | Mar 26 | Nov 10 | 229 d | 9a |
| Walla Walla | Mar 27 | Oct 31 | 218 d | 7a |
| Wallula | Apr 7 | Oct 22 | 198 d | 7b |
| Wapato | Apr 21 | Oct 15 | 177 d | 7a |
| Warden | Apr 27 | Oct 8 | 164 d | 7a |
| Washougal | Apr 29 | Oct 22 | 176 d | 8b |
| Washtucna | May 7 | Oct 4 | 150 d | 7a |
| Waterville | May 14 | Oct 1 | 140 d | 6b |
| Wauconda | May 6 | Oct 6 | 153 d | 6a |
| Wauna | Mar 11 | Nov 21 | 255 d | 8b |
| Waverly | May 7 | Sep 28 | 144 d | 6b |
| Wellpinit | Jun 6 | Sep 11 | 97 d | 7a |
| Wenatchee | Apr 4 | Oct 28 | 207 d | 7a |
| West Richland | Apr 6 | Oct 24 | 201 d | 7b |
| Westport | Mar 29 | Nov 7 | 223 d | 9a |
| White Salmon | Apr 20 | Oct 13 | 176 d | 7b |
| White Swan | Apr 21 | Oct 15 | 177 d | 7a |
| Wilbur | Jun 1 | Sep 22 | 113 d | 6b |
| Wilkeson | Apr 7 | Oct 30 | 206 d | 8b |
| Wilson Creek | May 2 | Oct 12 | 163 d | 6b |
| Winlock | Apr 5 | Oct 25 | 203 d | 8a |
| Winthrop | May 15 | Sep 22 | 130 d | 6b |
| Wishram | Apr 11 | Oct 26 | 198 d | 7b |
| Woodinville | Apr 17 | Oct 23 | 189 d | 8b |
| Woodland | Apr 18 | Nov 7 | 203 d | 8b |