Chewelah, WA 99138 Frost Dates
99138, near Chewelah, WA: the frost window
Typically, the last spring freeze lands around 05/16, roughly 261 days out. Fall's first freeze usually shows up around 09/15, roughly 120 days after the last spring frost.
Zone 6b (-5 to 0°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 Chewelah, not a forecast for this year.
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
At roughly 120 frost-free days, Chewelah places 39,080 of 40,283 ZIP codes in this dataset. Within WA, it ranks 658 of 700.
Learn more
Two guides worth reading on 99138: 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 99138 normal.