Chicago, IL 60615 Frost Dates
60615, 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.
Zone 6b (-5 to 0°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 Chicago, not a forecast for this year.
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.
The actual range around Chicago's last frost
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
At roughly 208 frost-free days, Chicago places 15,467 of 40,283 ZIP codes in this dataset. Within IL, it ranks 63 of 1,548.
Learn more
Two guides worth reading on 60615: zone vs. frost date, on why Zone 6b 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.