Grayslake, IL 60030 Frost Dates
60030, near Grayslake, IL: the frost window
Typically, the last spring freeze lands around 04/29, roughly 244 days out. Fall's first freeze usually shows up around 10/20, roughly 172 days after the last spring frost.
Grayslake sits in USDA Zone 5b (-15 to -10°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
Grayslake's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/29 isn't a guarantee
04/29 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/14 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/15 and only about 1 year in 10 sees frost after that.
Grayslake against the rest of the dataset
At roughly 172 frost-free days, Grayslake places 28,195 of 40,283 ZIP codes in this dataset. Within IL, it ranks 1,337 of 1,548.
Learn more
Two guides worth reading on 60030: local microclimates, on what one yard in Grayslake can differ from the 60030 normal, and zone vs. frost date, on why Zone 5b and Grayslake's frost date answer different questions.