Hillsdale, IL 61257 Frost Dates
When can you plant in Hillsdale, IL?
Typically, the last spring freeze lands around 04/20, roughly 235 days out. The first fall frost typically arrives around 10/20, about 180 frost-free days later.
Hillsdale sits in USDA Zone 5b (-15 to -10°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.
What to do before the first frost
About 8 weeks of growing season left in Hillsdale before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
04/20 is the middle of 30 years of NOAA records, not a promise. Plant by 04/06 and you're betting against frost in roughly 9 years out of 10. 05/06 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Hillsdale compares
Hillsdale's growing season runs about 180 days, ranking 25,032 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 975 of 1,548.
Learn more
zone vs. frost date covers why Zone 5b and Hillsdale's frost date answer different questions. the frost range covers how to read the range around Hillsdale's dates instead of trusting one.