Winnebago, IL 61088 Frost Dates
Frost dates for Winnebago, IL, ZIP 61088
Around 04/24 is the usual last spring frost, about 239 days away. The first fall frost typically arrives around 10/17, about 174 frost-free days later.
The USDA Plant Hardiness Zone Map puts Winnebago in Zone 5b (-15 to -10°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 5b around Winnebago has about 7 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 Winnebago's last frost
04/24 is the middle of 30 years of NOAA records, not a promise. Plant by 04/10 and you're betting against frost in roughly 9 years out of 10. 05/08 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Winnebago compares
Winnebago's growing season runs about 174 days, ranking 27,477 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 1,234 of 1,548.
Learn more
zone vs. frost date explains why Zone 5b and Winnebago's frost date answer different questions, and the frost range explains how to read the range around Winnebago's dates instead of trusting one.