Greendale, WI 53221 Frost Dates
Frost dates for Greendale, WI, ZIP 53221
Typically, the last spring freeze lands around 04/19, roughly 234 days out. The first fall frost typically arrives around 10/29, about 192 frost-free days later.
The USDA Plant Hardiness Zone Map puts Greendale in Zone 6a (-10 to -5°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 6a around Greendale 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 Greendale's last frost
04/19 is the middle of 30 years of NOAA records, not a promise. Plant by 04/06 and you're betting against frost in roughly 9 years out of 10. 05/02 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Greendale compares
About 192 days separate Greendale's last and first frost, putting it 20,204 of 40,283 ZIP codes nationally. Within WI, it ranks 2 of 860.
Learn more
zone vs. frost date explains why Zone 6a and Greendale's frost date answer different questions, and the frost range explains how to read the range around Greendale's dates instead of trusting one.