Seattle, WA 98102 Frost Dates
When can you plant in Seattle, WA?
Around 03/08 is the usual last spring frost, about 192 days away. The first fall frost typically arrives around 11/23, about 259 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
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
Seattle's growing season runs about 259 days, ranking 6,506 of 40,283 US ZIP codes measured here, longest to shortest. Within WA, it ranks 22 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 98102 normal.