Chicago, IL 60637 Frost Dates
60637, near Chicago, IL: the frost window
Around 04/10 is the usual last spring frost, about 225 days away. Fall's first freeze usually shows up around 11/05, roughly 208 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Chicago in Zone 6a (-10 to -5°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
Chicago's growing season runs out in roughly 10 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
04/10 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/29 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/25 and only about 1 year in 10 sees frost after that.
Chicago against the rest of the dataset
Chicago's growing season runs about 208 days, ranking 15,471 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 67 of 1,548.
Learn more
Two guides worth reading on 60637: zone vs. frost date, on why Zone 6a and Chicago's frost date answer different questions, and the frost range, on how to read the range around Chicago's dates instead of trusting one.