Windsor, IL 61957 Frost Dates
61957, near Windsor, IL: the frost window
Around 04/16 is the usual last spring frost, about 231 days away. Fall's first freeze usually shows up around 10/22, roughly 187 days after the last spring frost.
Zone 6a (-10 to -5°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Windsor, not a forecast for this year.
Stretching the season past the first frost
Windsor's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/16 isn't a guarantee
04/16 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/03 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/30 and only about 1 year in 10 sees frost after that.
Windsor against the rest of the dataset
Windsor's growing season runs about 187 days, ranking 22,495 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 769 of 1,548.
Learn more
Two guides worth reading on 61957: zone vs. frost date, on why Zone 6a and Windsor's frost date answer different questions, and the frost range, on how to read the range around Windsor's dates instead of trusting one.