Harrington, WA 99144 Frost Dates
99144, near Harrington, WA: the frost window
The last spring frost here typically falls around 05/31, about 276 days from today. Fall's first freeze usually shows up around 09/12, roughly 101 days after the last spring frost.
Harrington sits in USDA Zone 6b (-5 to 0°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
Harrington's growing season runs out in roughly 2 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 05/31 isn't a guarantee
05/31 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/10 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/28 and only about 1 year in 10 sees frost after that.
Harrington against the rest of the dataset
About 101 days separate Harrington's last and first frost, putting it 39,686 of 40,283 ZIP codes nationally. Within WA, it ranks 682 of 700.
Learn more
Two guides worth reading on 99144: the frost range, on how to read the range around Harrington's dates instead of trusting one, and local microclimates, on what one yard in Harrington can differ from the 99144 normal.