Chicago, IL 60642 Frost Dates
60642, near Chicago, IL: the frost window
Typically, the last spring freeze lands around 04/10, roughly 225 days out. Fall's first freeze usually shows up around 11/05, roughly 208 days after the last spring frost.
Chicago sits in USDA Zone 6a (-10 to -5°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a 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
About 208 days separate Chicago's last and first frost, putting it 15,472 of 40,283 ZIP codes nationally. Within IL, it ranks 68 of 1,548.
Learn more
Two guides worth reading on 60642: local microclimates, on what one yard in Chicago can differ from the 60642 normal, and zone vs. frost date, on why Zone 6a and Chicago's frost date answer different questions.