De Witt, IL 61735 Frost Dates
De Witt, IL: when does the frost end?
Typically, the last spring freeze lands around 04/23, roughly 238 days out. Fall's first freeze usually shows up around 10/13, roughly 170 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 De Witt, not a forecast for this year.
Stretching the season past the first frost
With roughly 7 weeks until De Witt's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/23 isn't a guarantee
04/23 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/09 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/09 and only about 1 year in 10 sees frost after that.
De Witt against the rest of the dataset
About 170 days separate De Witt's last and first frost, putting it 29,249 of 40,283 ZIP codes nationally. Within IL, it ranks 1,418 of 1,548.
Learn more
Before leaning on 61735's figures: the frost range explains how to read the range around De Witt's dates instead of trusting one, while local microclimates explains what one yard in De Witt can differ from the 61735 normal.