Bethalto, IL 62010 Frost Dates
62010, near Bethalto, 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 Bethalto, not a forecast for this year.
Stretching the season past the first frost
Bethalto'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.
Why 04/04 isn't a guarantee
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.
Bethalto against the rest of the dataset
At roughly 214 frost-free days, Bethalto places 14,239 of 40,283 ZIP codes in this dataset. Within IL, it ranks 15 of 1,548.
Learn more
Two guides worth reading on 62010: local microclimates, on what one yard in Bethalto can differ from the 62010 normal, and zone vs. frost date, on why Zone 6b and Bethalto's frost date answer different questions.