Palouse, WA 99161 Frost Dates
99161, near Palouse, WA: the frost window
Typically, the last spring freeze lands around 04/29, roughly 244 days out. Fall's first freeze usually shows up around 10/02, roughly 159 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 Palouse, not a forecast for this year.
Stretching the season past the first frost
Palouse's growing season runs out in roughly 5 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
04/29 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/07 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/14 and only about 1 year in 10 sees frost after that.
Palouse against the rest of the dataset
Palouse's growing season runs about 159 days, ranking 32,701 of 40,283 US ZIP codes measured here, longest to shortest. Within WA, it ranks 576 of 700.
Learn more
Two guides worth reading on 99161: local microclimates, on what one yard in Palouse can differ from the 99161 normal, and zone vs. frost date, on why Zone 6b and Palouse's frost date answer different questions.