Waterville, WA 98843 Frost Dates
Waterville, WA: when does the frost end?
Typically, the last spring freeze lands around 05/14, roughly 259 days out. Fall's first freeze usually shows up around 10/01, roughly 140 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 Waterville, not a forecast for this year.
Stretching the season past the first frost
With roughly 5 weeks until Waterville's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 05/14 isn't a guarantee
05/14 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/28 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/04 and only about 1 year in 10 sees frost after that.
Waterville against the rest of the dataset
At roughly 140 frost-free days, Waterville places 37,074 of 40,283 ZIP codes in this dataset. Within WA, it ranks 616 of 700.
Learn more
Before leaning on 98843's figures: zone vs. frost date explains why Zone 7a and Waterville's frost date answer different questions, while the frost range explains how to read the range around Waterville's dates instead of trusting one.