Frost dates in Washington
Across Washington, the typical last spring frost is around Apr 15 and the first fall frost around Oct 25. Your own dates depend on where you are in the state; find your county below.
Most of the state's last spring frosts fall between Mar 8 and May 13, and its first fall frosts between Sep 28 and Nov 21.
These are the dates with a 50% chance of a 32°F frost on or after (spring) or on or before (fall), so plan tender crops a week or two after the spring date and keep row cover handy. For dates at your exact ZIP code, use the zone and frost date lookup; for what to plant when, see the planting guide by frost date.
Hardiness zones in Washington: zone 6a, zone 6b, zone 7a, zone 7b, zone 8a, zone 8b, zone 9a, zone 9b
Frost dates by county in Washington
| County | Last spring frost | First fall frost | Growing season |
|---|---|---|---|
| Adams | May 7 | Oct 10 | About 156 days |
| Asotin | Apr 6 | Oct 26 | About 203 days |
| Benton | Apr 6 | Oct 24 | About 201 days |
| Chelan | Apr 21 | Oct 17 | About 179 days |
| Clallam | Apr 20 | Oct 26 | About 189 days |
| Clark | Apr 26 | Oct 18 | About 175 days |
| Columbia | Apr 28 | Oct 13 | About 168 days |
| Cowlitz | Apr 8 | Nov 5 | About 211 days |
| Douglas | Apr 26 | Oct 12 | About 169 days |
| Ferry | May 16 | Sep 15 | About 122 days |
| Franklin | Apr 30 | Oct 13 | About 166 days |
| Garfield | May 2 | Oct 4 | About 155 days |
| Grant | Apr 23 | Oct 12 | About 172 days |
| Grays Harbor | Apr 26 | Oct 22 | About 179 days |
| Island | Mar 13 | Nov 17 | About 249 days |
| Jefferson | Apr 11 | Nov 28 | About 231 days |
| King | Mar 13 | Nov 17 | About 249 days |
| Kitsap | Mar 29 | Nov 14 | About 230 days |
| Kittitas | May 13 | Oct 6 | About 146 days |
| Klickitat | May 12 | Oct 11 | About 152 days |
| Lewis | Apr 7 | Oct 25 | About 201 days |
| Lincoln | May 31 | Sep 22 | About 114 days |
| Mason | Mar 24 | Nov 15 | About 236 days |
| Okanogan | Apr 30 | Oct 7 | About 160 days |
| Pacific | Apr 6 | Oct 26 | About 203 days |
| Pend Oreille | May 12 | Oct 4 | About 145 days |
| Pierce | Mar 11 | Nov 14 | About 248 days |
| San Juan | Feb 26 | Nov 29 | About 276 days |
| Skagit | Mar 27 | Nov 3 | About 221 days |
| Skamania | Apr 20 | Oct 22 | About 185 days |
| Snohomish | Mar 24 | Nov 2 | About 223 days |
| Spokane | Apr 26 | Oct 15 | About 172 days |
| Stevens | May 16 | Sep 15 | About 122 days |
| Thurston | Apr 29 | Oct 14 | About 168 days |
| Wahkiakum | Apr 24 | Oct 22 | About 181 days |
| Walla Walla | Apr 28 | Oct 22 | About 177 days |
| Whatcom | Apr 1 | Nov 2 | About 215 days |
| Whitman | May 6 | Sep 29 | About 146 days |
| Yakima | Apr 21 | Oct 15 | About 177 days |
Source: NOAA NCEI U.S. Climate Normals 1991–2020, 50% probability of 32°F, from the weather station nearest each ZIP code; each county shows the middle value across its ZIP codes. Hills, valleys and cities can run a week or more earlier or later.