Bunker Hill, IL 62021 Frost Dates
62021, near Bunker Hill, IL: the frost window
Typically, the last spring freeze lands around 04/04, roughly 219 days out. Fall's first freeze usually shows up around 11/05, roughly 214 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 Bunker Hill, not a forecast for this year.
Stretching the season past the first frost
Bunker Hill's growing season runs out in roughly 10 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
04/04 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/18 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/19 and only about 1 year in 10 sees frost after that.
Bunker Hill against the rest of the dataset
Bunker Hill's growing season runs about 214 days, ranking 14,272 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 21 of 1,548.
Learn more
Two guides worth reading on 62021: zone vs. frost date, on why Zone 6b and Bunker Hill's frost date answer different questions, and the frost range, on how to read the range around Bunker Hill's dates instead of trusting one.