Harwood Heights, IL 60641 Frost Dates
Harwood Heights, IL: when does the frost end?
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 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 Harwood Heights, not a forecast for this year.
Stretching the season past the first frost
With roughly 10 weeks until Harwood Heights's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Harwood Heights'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.
Harwood Heights against the rest of the dataset
About 208 days separate Harwood Heights's last and first frost, putting it 15,560 of 40,283 ZIP codes nationally. Within IL, it ranks 85 of 1,548.
Learn more
Before leaning on 60641's figures: zone vs. frost date explains why Zone 6a and Harwood Heights's frost date answer different questions, while the frost range explains how to read the range around Harwood Heights's dates instead of trusting one.