Black River Falls, WI 54615 Frost Dates
Frost dates for Black River Falls, WI, ZIP 54615
Around 05/09 is the usual last spring frost, about 254 days away. The first fall frost typically arrives around 10/01, about 143 frost-free days later.
The USDA Plant Hardiness Zone Map puts Black River Falls in Zone 4b (-25 to -20°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 4b around Black River Falls 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 Black River Falls's last frost
05/09 is the middle of 30 years of NOAA records, not a promise. Plant by 04/28 and you're betting against frost in roughly 9 years out of 10. 05/23 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Black River Falls compares
At roughly 143 frost-free days, Black River Falls places 36,523 of 40,283 ZIP codes in this dataset. Within WI, it ranks 689 of 860.
Learn more
zone vs. frost date explains why Zone 4b and Black River Falls's frost date answer different questions, and the frost range explains how to read the range around Black River Falls's dates instead of trusting one.