Chewelah, WA 99109 Frost Dates
99109, near Chewelah, WA: the frost window
Around 05/16 is the usual last spring frost, about 261 days away. Fall's first freeze usually shows up around 09/15, roughly 120 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Chewelah in Zone 6a (-10 to -5°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
Chewelah's growing season runs out in roughly 3 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 Chewelah's last frost
05/16 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/30 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/07 and only about 1 year in 10 sees frost after that.
Chewelah against the rest of the dataset
About 120 days separate Chewelah's last and first frost, putting it 39,078 of 40,283 ZIP codes nationally. Within WA, it ranks 656 of 700.
Learn more
Two guides worth reading on 99109: the frost range, on how to read the range around Chewelah's dates instead of trusting one, and local microclimates, on what one yard in Chewelah can differ from the 99109 normal.