Mount Zion, IL 62549 Frost Dates
Mount Zion, IL: when does the frost end?
Typically, the last spring freeze lands around 04/16, roughly 231 days out. Fall's first freeze usually shows up around 10/22, roughly 187 days after the last spring frost.
Zone 6a (-10 to -5°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 Mount Zion, not a forecast for this year.
Stretching the season past the first frost
With roughly 8 weeks until Mount Zion's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/16 isn't a guarantee
04/16 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/03 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/30 and only about 1 year in 10 sees frost after that.
Mount Zion against the rest of the dataset
About 187 days separate Mount Zion's last and first frost, putting it 22,353 of 40,283 ZIP codes nationally. Within IL, it ranks 718 of 1,548.
Learn more
Before leaning on 62549's figures: zone vs. frost date explains why Zone 6a and Mount Zion's frost date answer different questions, while the frost range explains how to read the range around Mount Zion's dates instead of trusting one.