Winthrop, WA 98852 Frost Dates
Winthrop, WA: when does the frost end?
Around 04/27 is the usual last spring frost, about 242 days away. Fall's first freeze usually shows up around 10/17, roughly 173 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 Winthrop, not a forecast for this year.
Stretching the season past the first frost
With roughly 7 weeks until Winthrop's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/27 isn't a guarantee
04/27 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/12 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/12 and only about 1 year in 10 sees frost after that.
Winthrop against the rest of the dataset
At roughly 173 frost-free days, Winthrop places 28,031 of 40,283 ZIP codes in this dataset. Within WA, it ranks 483 of 700.
Learn more
Before leaning on 98852's figures: local microclimates explains what one yard in Winthrop can differ from the 98852 normal, while zone vs. frost date explains why Zone 6b and Winthrop's frost date answer different questions.