Altamont, IL 62411 Frost Dates
62411, near Altamont, IL: the frost window
Around 04/03 is the usual last spring frost, about 218 days away. Fall's first freeze usually shows up around 10/24, roughly 202 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 Altamont, not a forecast for this year.
Stretching the season past the first frost
Altamont's growing season runs out in roughly 8 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 Altamont's last frost
04/03 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/19 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/25 and only about 1 year in 10 sees frost after that.
Altamont against the rest of the dataset
About 202 days separate Altamont's last and first frost, putting it 17,259 of 40,283 ZIP codes nationally. Within IL, it ranks 177 of 1,548.
Learn more
Two guides worth reading on 62411: local microclimates, on what one yard in Altamont can differ from the 62411 normal, and zone vs. frost date, on why Zone 6b and Altamont's frost date answer different questions.