Union, IL 60180 Frost Dates
60180, near Union, IL: the frost window
Around 04/28 is the usual last spring frost, about 243 days away. Fall's first freeze usually shows up around 10/12, roughly 166 days after the last spring frost.
Union 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
Union's growing season runs out in roughly 6 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/28 isn't a guarantee
04/28 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/15 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/14 and only about 1 year in 10 sees frost after that.
Union against the rest of the dataset
Union's growing season runs about 166 days, ranking 30,424 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 1,484 of 1,548.
Learn more
Two guides worth reading on 60180: the frost range, on how to read the range around Union's dates instead of trusting one, and local microclimates, on what one yard in Union can differ from the 60180 normal.