Marcus, WA 99146 Frost Dates
Frost dates for Marcus, WA, ZIP 99146
The last spring frost here typically falls around 05/08, about 253 days from today. The first fall frost typically arrives around 10/01, about 143 frost-free days later.
Zone 6b (-5 to 0°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 Marcus, not a forecast for this year.
What to do before the first frost
Zone 6b around Marcus has about 5 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.
Why 05/08 isn't a guarantee
05/08 is the middle of 30 years of NOAA records, not a promise. Plant by 04/27 and you're betting against frost in roughly 9 years out of 10. 05/26 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Marcus compares
At roughly 143 frost-free days, Marcus places 36,641 of 40,283 ZIP codes in this dataset. Within WA, it ranks 610 of 700.
Learn more
local microclimates explains what one yard in Marcus can differ from the 99146 normal, and zone vs. frost date explains why Zone 6b and Marcus's frost date answer different questions.