Birchwood, WI 54857 Frost Dates
Frost dates for Birchwood, WI, ZIP 54857
The last spring frost here typically falls around 05/09, about 254 days from today. The first fall frost typically arrives around 09/29, about 140 frost-free days later.
The USDA Plant Hardiness Zone Map puts Birchwood in Zone 4a (-30 to -25°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 4a around Birchwood 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 05/09 isn't a guarantee
05/09 is the middle of 30 years of NOAA records, not a promise. Plant by 04/26 and you're betting against frost in roughly 9 years out of 10. 05/27 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Birchwood compares
At roughly 140 frost-free days, Birchwood places 37,135 of 40,283 ZIP codes in this dataset. Within WI, it ranks 718 of 860.
Learn more
zone vs. frost date explains why Zone 4a and Birchwood's frost date answer different questions, and the frost range explains how to read the range around Birchwood's dates instead of trusting one.