Duvall, WA 98077 Frost Dates
98077, near Duvall, WA: the frost window
Around 04/17 is the usual last spring frost, about 232 days away. Fall's first freeze usually shows up around 10/23, roughly 188 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Duvall in Zone 8b (15 to 20°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
Duvall's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/17 isn't a guarantee
04/17 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/29 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/07 and only about 1 year in 10 sees frost after that.
Duvall against the rest of the dataset
Duvall's growing season runs about 188 days, ranking 21,934 of 40,283 US ZIP codes measured here, longest to shortest. Within WA, it ranks 413 of 700.
Learn more
Two guides worth reading on 98077: zone vs. frost date, on why Zone 8b and Duvall's frost date answer different questions, and the frost range, on how to read the range around Duvall's dates instead of trusting one.