Washington frost dates

Across Washington, the average last spring frost is around April 20 and the average first fall frost around October 15 — roughly 178 frost-free days. USDA zones 4b, 5b, 6b, 7b, 8a, 8b, 9a.

Risk you accept	Last spring frost by	First fall frost by
Cautious (~10%)	May 4	October 1
Average (~50%)	April 20	October 15
Gambler (~90%)	April 6	October 29

Washington spans a wide range of elevations and climates — your town’s dates can differ from the state average by two weeks or more. Look up your exact ZIP.

→ Turn these into sowing dates with the Washington planting calendar, or look up an exact ZIP code.

Statewide average from NOAA/NCEI freeze normals. Cautious/gambler dates are about two weeks either side of the average.