Kennewick, WA 99337 Frost Dates
Frost dates for Kennewick, WA, ZIP 99337
Around 03/28 is the usual last spring frost, about 212 days away. The first fall frost typically arrives around 10/30, about 216 frost-free days later.
Zone 7b (5 to 10°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 Kennewick, not a forecast for this year.
What to do before the first frost
Zone 7b around Kennewick has about 9 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.
The actual range around Kennewick's last frost
03/28 is the middle of 30 years of NOAA records, not a promise. Plant by 03/09 and you're betting against frost in roughly 9 years out of 10. 04/10 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Kennewick compares
At roughly 216 frost-free days, Kennewick places 13,703 of 40,283 ZIP codes in this dataset. Within WA, it ranks 252 of 700.
Learn more
the frost range explains how to read the range around Kennewick's dates instead of trusting one, and local microclimates explains what one yard in Kennewick can differ from the 99337 normal.