Birnamwood, WI 54414 Frost Dates
Frost dates for Birnamwood, WI, ZIP 54414
Around 05/06 is the usual last spring frost, about 251 days away. The first fall frost typically arrives around 10/05, about 150 frost-free days later.
Birnamwood sits in USDA Zone 4b (-25 to -20°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
Zone 4b around Birnamwood 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.
The actual range around Birnamwood's last frost
05/06 is the middle of 30 years of NOAA records, not a promise. Plant by 04/24 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 Birnamwood compares
At roughly 150 frost-free days, Birnamwood places 35,355 of 40,283 ZIP codes in this dataset. Within WI, it ranks 576 of 860.
Learn more
zone vs. frost date explains why Zone 4b and Birnamwood's frost date answer different questions, and the frost range explains how to read the range around Birnamwood's dates instead of trusting one.