Bolingbrook, IL 60440 Frost Dates
Bolingbrook, IL: when does the frost end?
Around 04/20 is the usual last spring frost, about 235 days away. Fall's first freeze usually shows up around 10/22, roughly 184 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 Bolingbrook, not a forecast for this year.
Stretching the season past the first frost
With roughly 8 weeks until Bolingbrook's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/20 isn't a guarantee
04/20 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/07 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/06 and only about 1 year in 10 sees frost after that.
Bolingbrook against the rest of the dataset
About 184 days separate Bolingbrook's last and first frost, putting it 23,403 of 40,283 ZIP codes nationally. Within IL, it ranks 862 of 1,548.
Learn more
Before leaning on 60440's figures: local microclimates explains what one yard in Bolingbrook can differ from the 60440 normal, while zone vs. frost date explains why Zone 6a and Bolingbrook's frost date answer different questions.