Potomac, IL 61812 Frost Dates
Frost dates for Potomac, IL, ZIP 61812
The last spring frost here typically falls around 04/20, about 235 days from today. The first fall frost typically arrives around 10/21, about 182 frost-free days later.
Zone 6a (-10 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 Potomac, not a forecast for this year.
What to do before the first frost
Zone 6a around Potomac has about 8 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 Potomac's last frost
04/20 is the middle of 30 years of NOAA records, not a promise. Plant by 04/07 and you're betting against frost in roughly 9 years out of 10. 05/07 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Potomac compares
About 182 days separate Potomac's last and first frost, putting it 24,263 of 40,283 ZIP codes nationally. Within IL, it ranks 905 of 1,548.
Learn more
the frost range explains how to read the range around Potomac's dates instead of trusting one, and local microclimates explains what one yard in Potomac can differ from the 61812 normal.