Cortland, IL 60112 Frost Dates
Frost dates for Cortland, IL, ZIP 60112
The last spring frost here typically falls around 04/24, about 239 days from today. The first fall frost typically arrives around 10/18, about 177 frost-free days later.
Cortland 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
Zone 5b around Cortland has about 7 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
The actual range around Cortland's last frost
04/24 is the middle of 30 years of NOAA records, not a promise. Plant by 04/09 and you're betting against frost in roughly 9 years out of 10. 05/10 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Cortland compares
About 177 days separate Cortland's last and first frost, putting it 26,108 of 40,283 ZIP codes nationally. Within IL, it ranks 1,124 of 1,548.
Learn more
local microclimates explains what one yard in Cortland can differ from the 60112 normal, and zone vs. frost date explains why Zone 5b and Cortland's frost date answer different questions.