Mount Vernon, IL 62864 Frost Dates
62864, near Mount Vernon, IL: the frost window
Around 04/11 is the usual last spring frost, about 226 days away. Fall's first freeze usually shows up around 10/22, roughly 193 days after the last spring frost.
Mount Vernon sits in USDA Zone 6b (-5 to 0°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
Mount Vernon'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
04/11 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/30 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/26 and only about 1 year in 10 sees frost after that.
Mount Vernon against the rest of the dataset
Mount Vernon's growing season runs about 193 days, ranking 19,758 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 384 of 1,548.
Learn more
Two guides worth reading on 62864: the frost range, on how to read the range around Mount Vernon's dates instead of trusting one, and local microclimates, on what one yard in Mount Vernon can differ from the 62864 normal.