Westby, WI 54667 Frost Dates
Frost dates for Westby, WI, ZIP 54667
Typically, the last spring freeze lands around 05/07, roughly 252 days out. The first fall frost typically arrives around 10/02, about 148 frost-free days later.
Zone 5a (-20 to -15°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 Westby, not a forecast for this year.
What to do before the first frost
Zone 5a around Westby 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 05/07 isn't a guarantee
05/07 is the middle of 30 years of NOAA records, not a promise. Plant by 04/23 and you're betting against frost in roughly 9 years out of 10. 05/21 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Westby compares
Westby's growing season runs about 148 days, ranking 35,726 of 40,283 US ZIP codes measured here, longest to shortest. Within WI, it ranks 609 of 860.
Learn more
local microclimates explains what one yard in Westby can differ from the 54667 normal, and zone vs. frost date explains why Zone 5a and Westby's frost date answer different questions.