The National Weather Service office in Spokane has issued a Frost Advisory affecting five zones across northeastern Washington, warning residents and gardeners of potentially damaging overnight temperatures expected in the early morning hours of Friday, May 15, 2026.
What the Advisory Covers
The advisory, issued by the National Weather Service Spokane at 10:58 a.m. PDT Thursday, is in effect from 2 a.m. to 8 a.m. PDT Friday across three forecast zones: the Northeast Mountains, the Okanogan Highlands, and Western Okanogan County.
The affected area spans dozens of communities, including Winthrop, Colville, Republic, Twisp, Chewelah, Deer Park, Kettle Falls, Conconully, Northport, Newport, and Metaline Falls, among others.
Forecast low temperatures are expected to range between 33 and 37 degrees Fahrenheit, conditions sufficient to produce frost on exposed surfaces and sensitive vegetation.
Risk to Gardens and Agriculture
The primary concern outlined in the advisory is damage to outdoor plants. A frost advisory is issued when temperatures are forecast to fall between 32°F and 36°F — conditions under which a light frost can kill the tops of tender plants while leaving lower portions intact. The NWS warns that sensitive outdoor plants may be killed if left uncovered during the advisory window…