Sparland, IL 61565 Frost Dates
61565, near Sparland, IL: the frost window
Around 04/20 is the usual last spring frost, about 235 days away. Fall's first freeze usually shows up around 10/17, roughly 178 days after the last spring frost.
Sparland sits in USDA Zone 5b (-15 to -10°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
Sparland'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 04/20 isn't a guarantee
04/20 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/05 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/07 and only about 1 year in 10 sees frost after that.
Sparland against the rest of the dataset
At roughly 178 frost-free days, Sparland places 25,893 of 40,283 ZIP codes in this dataset. Within IL, it ranks 1,103 of 1,548.
Learn more
Two guides worth reading on 61565: zone vs. frost date, on why Zone 5b and Sparland's frost date answer different questions, and the frost range, on how to read the range around Sparland's dates instead of trusting one.