Ione, WA 99139 Frost Dates
When can you plant in Ione, WA?
Typically, the last spring freeze lands around 05/04, roughly 249 days out. The first fall frost typically arrives around 10/04, about 153 frost-free days later.
Ione sits in USDA Zone 6a (-10 to -5°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.
What to do before the first frost
About 5 weeks of growing season left in Ione before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Ione's last frost
05/04 is the middle of 30 years of NOAA records, not a promise. Plant by 04/20 and you're betting against frost in roughly 9 years out of 10. 05/18 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Ione compares
About 153 days separate Ione's last and first frost, putting it 34,603 of 40,283 ZIP codes nationally. Within WA, it ranks 590 of 700.
Learn more
local microclimates covers what one yard in Ione can differ from the 99139 normal. zone vs. frost date covers why Zone 6a and Ione's frost date answer different questions.