Seattle, WA 98199 Frost Dates
When can you plant in Seattle, WA?
Typically, the last spring freeze lands around 03/08, roughly 192 days out. The first fall frost typically arrives around 11/23, about 259 frost-free days later.
Zone 9a (20 to 25°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Seattle, not a forecast for this year.
What to do before the first frost
About 12 weeks of growing season left in Seattle before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 03/08 isn't a guarantee
03/08 is the middle of 30 years of NOAA records, not a promise. Plant by 02/13 and you're betting against frost in roughly 9 years out of 10. 03/29 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Seattle compares
About 259 days separate Seattle's last and first frost, putting it 6,512 of 40,283 ZIP codes nationally. Within WA, it ranks 28 of 700.
Learn more
the frost range covers how to read the range around Seattle's dates instead of trusting one. local microclimates covers what one yard in Seattle can differ from the 98199 normal.