Manhattan, IL 60442 Frost Dates
Manhattan, IL: when does the frost end?
Around 04/19 is the usual last spring frost, about 234 days away. Fall's first freeze usually shows up around 10/25, roughly 188 days after the last spring frost.
Manhattan sits in USDA Zone 6a (-10 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 8 weeks until Manhattan's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/19 isn't a guarantee
04/19 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 05/07 and only about 1 year in 10 sees frost after that.
Manhattan against the rest of the dataset
Manhattan's growing season runs about 188 days, ranking 21,920 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 671 of 1,548.
Learn more
Before leaning on 60442's figures: local microclimates explains what one yard in Manhattan can differ from the 60442 normal, while zone vs. frost date explains why Zone 6a and Manhattan's frost date answer different questions.