Harrington, WA 99147 Frost Dates
When can you plant in Harrington, WA?
Around 05/31 is the usual last spring frost, about 276 days away. The first fall frost typically arrives around 09/12, about 101 frost-free days later.
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 Harrington, not a forecast for this year.
What to do before the first frost
About 2 weeks of growing season left in Harrington before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 05/31 isn't a guarantee
05/31 is the middle of 30 years of NOAA records, not a promise. Plant by 05/10 and you're betting against frost in roughly 9 years out of 10. 06/28 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Harrington compares
At roughly 101 frost-free days, Harrington places 39,687 of 40,283 ZIP codes in this dataset. Within WA, it ranks 683 of 700.
Learn more
zone vs. frost date covers why Zone 7a and Harrington's frost date answer different questions. the frost range covers how to read the range around Harrington's dates instead of trusting one.