Tieton, WA 98937 Frost Dates
98937, near Tieton, WA: the frost window
Around 04/08 is the usual last spring frost, about 223 days away. Fall's first freeze usually shows up around 10/23, roughly 196 days after the last spring frost.
Zone 7a (0 to 5°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 Tieton, not a forecast for this year.
Stretching the season past the first frost
Tieton's growing season runs out in roughly 8 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 Tieton's last frost
04/08 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/23 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/28 and only about 1 year in 10 sees frost after that.
Tieton against the rest of the dataset
Tieton's growing season runs about 196 days, ranking 19,012 of 40,283 US ZIP codes measured here, longest to shortest. Within WA, it ranks 354 of 700.
Learn more
Two guides worth reading on 98937: zone vs. frost date, on why Zone 7a and Tieton's frost date answer different questions, and the frost range, on how to read the range around Tieton's dates instead of trusting one.