Prescott, WA 99348 Frost Dates
99348, near Prescott, WA: the frost window
Typically, the last spring freeze lands around 03/27, roughly 211 days out. Fall's first freeze usually shows up around 10/31, roughly 219 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Prescott in Zone 7a (0 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
Prescott's growing season runs out in roughly 9 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 03/27 isn't a guarantee
03/27 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/03 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/22 and only about 1 year in 10 sees frost after that.
Prescott against the rest of the dataset
At roughly 219 frost-free days, Prescott places 13,101 of 40,283 ZIP codes in this dataset. Within WA, it ranks 246 of 700.
Learn more
Two guides worth reading on 99348: the frost range, on how to read the range around Prescott's dates instead of trusting one, and local microclimates, on what one yard in Prescott can differ from the 99348 normal.