Lewistown, IL 61542 Frost Dates
61542, near Lewistown, IL: the frost window
The last spring frost here typically falls around 04/17, about 232 days from today. Fall's first freeze usually shows up around 10/19, roughly 185 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 Lewistown, not a forecast for this year.
Stretching the season past the first frost
Lewistown'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.
The actual range around Lewistown's last frost
04/17 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/02 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/03 and only about 1 year in 10 sees frost after that.
Lewistown against the rest of the dataset
About 185 days separate Lewistown's last and first frost, putting it 23,200 of 40,283 ZIP codes nationally. Within IL, it ranks 831 of 1,548.
Learn more
Two guides worth reading on 61542: zone vs. frost date, on why Zone 6a and Lewistown's frost date answer different questions, and the frost range, on how to read the range around Lewistown's dates instead of trusting one.