Flat Rock, IL 62427 Frost Dates
Flat Rock, IL: when does the frost end?
The last spring frost here typically falls around 04/08, about 223 days from today. Fall's first freeze usually shows up around 10/26, roughly 200 days after the last spring frost.
Zone 6b (-5 to 0°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 Flat Rock, not a forecast for this year.
Stretching the season past the first frost
With roughly 8 weeks until Flat Rock'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
04/08 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/26 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/22 and only about 1 year in 10 sees frost after that.
Flat Rock against the rest of the dataset
Flat Rock's growing season runs about 200 days, ranking 17,893 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 285 of 1,548.
Learn more
Before leaning on 62427's figures: local microclimates explains what one yard in Flat Rock can differ from the 62427 normal, while zone vs. frost date explains why Zone 6b and Flat Rock's frost date answer different questions.