Renton, WA 98059 Frost Dates
98059, near Renton, WA: the frost window
Around 03/20 is the usual last spring frost, about 204 days away. Fall's first freeze usually shows up around 11/10, roughly 233 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Renton 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
Renton's growing season runs out in roughly 11 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around Renton's last frost
03/20 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 02/27 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/08 and only about 1 year in 10 sees frost after that.
Renton against the rest of the dataset
Renton's growing season runs about 233 days, ranking 9,845 of 40,283 US ZIP codes measured here, longest to shortest. Within WA, it ranks 176 of 700.
Learn more
Two guides worth reading on 98059: the frost range, on how to read the range around Renton's dates instead of trusting one, and local microclimates, on what one yard in Renton can differ from the 98059 normal.