Alto Pass, IL 62998 Frost Dates
Alto Pass, IL: when does the frost end?
Around 04/07 is the usual last spring frost, about 222 days away. Fall's first freeze usually shows up around 10/29, roughly 202 days after the last spring frost.
Alto Pass sits in USDA Zone 7a (0 to 5°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
With roughly 9 weeks until Alto Pass's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
04/07 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/24 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/22 and only about 1 year in 10 sees frost after that.
Alto Pass against the rest of the dataset
Alto Pass's growing season runs about 202 days, ranking 17,352 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 189 of 1,548.
Learn more
Before leaning on 62998's figures: zone vs. frost date explains why Zone 7a and Alto Pass's frost date answer different questions, while the frost range explains how to read the range around Alto Pass's dates instead of trusting one.