St. Elmo, IL 62458 Frost Dates
62458, near St. Elmo, 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 St. Elmo, not a forecast for this year.
Stretching the season past the first frost
St. Elmo'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.
How much risk comes with planting early here
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.
St. Elmo against the rest of the dataset
St. Elmo's growing season runs about 202 days, ranking 17,277 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 178 of 1,548.
Learn more
Two guides worth reading on 62458: the frost range, on how to read the range around St. Elmo's dates instead of trusting one, and local microclimates, on what one yard in St. Elmo can differ from the 62458 normal.