Seattle, WA 98116 Frost Dates
Seattle, WA: when does the frost end?
The last spring frost here typically falls around 03/13, about 197 days from today. Fall's first freeze usually shows up around 11/17, roughly 247 days after the last spring frost.
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.
Stretching the season past the first frost
With roughly 12 weeks until Seattle's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Seattle's last frost
03/13 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 02/20 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/01 and only about 1 year in 10 sees frost after that.
Seattle against the rest of the dataset
Seattle's growing season runs about 247 days, ranking 7,748 of 40,283 US ZIP codes measured here, longest to shortest. Within WA, it ranks 133 of 700.
Learn more
Before leaning on 98116's figures: local microclimates explains what one yard in Seattle can differ from the 98116 normal, while zone vs. frost date explains why Zone 9a and Seattle's frost date answer different questions.