Burien, WA 98166 Frost Dates
Burien, WA: when does the frost end?
Around 03/02 is the usual last spring frost, about 186 days away. Fall's first freeze usually shows up around 11/23, roughly 266 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Burien in Zone 9a (20 to 25°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
With roughly 12 weeks until Burien's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 03/02 isn't a guarantee
03/02 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 02/05 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 03/23 and only about 1 year in 10 sees frost after that.
Burien against the rest of the dataset
About 266 days separate Burien's last and first frost, putting it 5,913 of 40,283 ZIP codes nationally. Within WA, it ranks 17 of 700.
Learn more
Before leaning on 98166's figures: local microclimates explains what one yard in Burien can differ from the 98166 normal, while zone vs. frost date explains why Zone 9a and Burien's frost date answer different questions.