Seattle, WA 98144 Frost Dates
Frost dates for Seattle, WA, ZIP 98144
Typically, the last spring freeze lands around 03/13, roughly 197 days out. The first fall frost typically arrives around 11/17, about 247 frost-free days later.
The USDA Plant Hardiness Zone Map puts Seattle in Zone 9a (20 to 25°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 9a around Seattle has about 12 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
How much risk comes with planting early here
03/13 is the middle of 30 years of NOAA records, not a promise. Plant by 02/20 and you're betting against frost in roughly 9 years out of 10. 04/01 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Seattle compares
At roughly 247 frost-free days, Seattle places 7,752 of 40,283 ZIP codes in this dataset. Within WA, it ranks 137 of 700.
Learn more
zone vs. frost date explains why Zone 9a and Seattle's frost date answer different questions, and the frost range explains how to read the range around Seattle's dates instead of trusting one.