Hamilton, WA 98255 Frost Dates
98255, near Hamilton, WA: the frost window
Around 03/28 is the usual last spring frost, about 212 days away. Fall's first freeze usually shows up around 11/14, roughly 229 days after the last spring frost.
Hamilton sits in USDA Zone 8b (15 to 20°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
Hamilton's growing season runs out in roughly 11 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 Hamilton's last frost
03/28 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/07 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/19 and only about 1 year in 10 sees frost after that.
Hamilton against the rest of the dataset
Hamilton's growing season runs about 229 days, ranking 10,658 of 40,283 US ZIP codes measured here, longest to shortest. Within WA, it ranks 181 of 700.
Learn more
Two guides worth reading on 98255: the frost range, on how to read the range around Hamilton's dates instead of trusting one, and local microclimates, on what one yard in Hamilton can differ from the 98255 normal.