Zillah, WA 98953 Frost Dates
Frost dates for Zillah, WA, ZIP 98953
Typically, the last spring freeze lands around 05/04, roughly 249 days out. The first fall frost typically arrives around 10/10, about 155 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 Zillah, not a forecast for this year.
What to do before the first frost
Zone 7a around Zillah has about 6 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
How much risk comes with planting early here
05/04 is the middle of 30 years of NOAA records, not a promise. Plant by 04/21 and you're betting against frost in roughly 9 years out of 10. 05/23 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Zillah compares
At roughly 155 frost-free days, Zillah places 33,980 of 40,283 ZIP codes in this dataset. Within WA, it ranks 585 of 700.
Learn more
zone vs. frost date explains why Zone 7a and Zillah's frost date answer different questions, and the frost range explains how to read the range around Zillah's dates instead of trusting one.