Rantoul, IL 61866 Frost Dates
61866, near Rantoul, IL: the frost window
The last spring frost here typically falls around 04/21, about 236 days from today. Fall's first freeze usually shows up around 10/18, roughly 179 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Rantoul in Zone 6a (-10 to -5°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
Rantoul's growing season runs out in roughly 7 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/21 isn't a guarantee
04/21 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.
Rantoul against the rest of the dataset
About 179 days separate Rantoul's last and first frost, putting it 25,240 of 40,283 ZIP codes nationally. Within IL, it ranks 1,012 of 1,548.
Learn more
Two guides worth reading on 61866: local microclimates, on what one yard in Rantoul can differ from the 61866 normal, and zone vs. frost date, on why Zone 6a and Rantoul's frost date answer different questions.