Bonney Lake, WA 98390 Frost Dates
Frost dates for Bonney Lake, WA, ZIP 98390
Typically, the last spring freeze lands around 04/11, roughly 226 days out. The first fall frost typically arrives around 10/30, about 202 frost-free days later.
Zone 8b (15 to 20°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 Bonney Lake, not a forecast for this year.
What to do before the first frost
Zone 8b around Bonney Lake 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 Bonney Lake's last frost
04/11 is the middle of 30 years of NOAA records, not a promise. Plant by 03/23 and you're betting against frost in roughly 9 years out of 10. 04/29 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Bonney Lake compares
About 202 days separate Bonney Lake's last and first frost, putting it 17,151 of 40,283 ZIP codes nationally. Within WA, it ranks 292 of 700.
Learn more
the frost range explains how to read the range around Bonney Lake's dates instead of trusting one, and local microclimates explains what one yard in Bonney Lake can differ from the 98390 normal.