Chicago, IL 60499 Frost Dates
Chicago, IL: when does the frost end?
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.
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 Chicago, not a forecast for this year.
Stretching the season past the first frost
With roughly 9 weeks until Chicago's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
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
At roughly 201 frost-free days, Chicago places 17,417 of 40,283 ZIP codes in this dataset. Within IL, it ranks 211 of 1,548.
Learn more
Before leaning on 60499's figures: local microclimates explains what one yard in Chicago can differ from the 60499 normal, while zone vs. frost date explains why Zone 6a and Chicago's frost date answer different questions.