Harvard, IL 60033 Frost Dates
Harvard, IL: when does the frost end?
The last spring frost here typically falls around 04/28, about 243 days from today. Fall's first freeze usually shows up around 10/12, roughly 166 days after the last spring frost.
Zone 5b (-15 to -10°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 Harvard, not a forecast for this year.
Stretching the season past the first frost
With roughly 6 weeks until Harvard's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/28 isn't a guarantee
04/28 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/15 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/14 and only about 1 year in 10 sees frost after that.
Harvard against the rest of the dataset
Harvard's growing season runs about 166 days, ranking 30,321 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 1,474 of 1,548.
Learn more
Before leaning on 60033's figures: the frost range explains how to read the range around Harvard's dates instead of trusting one, while local microclimates explains what one yard in Harvard can differ from the 60033 normal.