Alto Pass, IL 62905 Frost Dates
62905, near Alto Pass, IL: the frost window
Around 04/09 is the usual last spring frost, about 224 days away. Fall's first freeze usually shows up around 10/22, roughly 195 days after the last spring frost.
Zone 7a (0 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 Alto Pass, not a forecast for this year.
Stretching the season past the first frost
Alto Pass's growing season runs out in roughly 8 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
04/09 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/25 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/25 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 195 days, ranking 19,348 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 349 of 1,548.
Learn more
Two guides worth reading on 62905: zone vs. frost date, on why Zone 7a and Alto Pass's frost date answer different questions, and the frost range, on how to read the range around Alto Pass's dates instead of trusting one.