Chicago, IL 60303 Frost Dates
60303, near Chicago, IL: the frost window
Around 04/11 is the usual last spring frost, about 226 days away. Fall's first freeze usually shows up around 10/31, roughly 201 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 9 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
04/11 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/30 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/27 and only about 1 year in 10 sees frost after that.
Chicago against the rest of the dataset
Chicago's growing season runs about 201 days, ranking 17,414 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 208 of 1,548.
Learn more
Two guides worth reading on 60303: the frost range, on how to read the range around Chicago's dates instead of trusting one, and local microclimates, on what one yard in Chicago can differ from the 60303 normal.