Humboldt, IL 61931 Frost Dates
Frost dates for Humboldt, IL, ZIP 61931
Typically, the last spring freeze lands around 04/11, roughly 226 days out. The first fall frost typically arrives around 10/29, about 199 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 Humboldt, not a forecast for this year.
What to do before the first frost
Zone 6a around Humboldt has about 9 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.
How much risk comes with planting early here
04/11 is the middle of 30 years of NOAA records, not a promise. Plant by 03/31 and you're betting against frost in roughly 9 years out of 10. 04/28 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Humboldt compares
At roughly 199 frost-free days, Humboldt places 18,203 of 40,283 ZIP codes in this dataset. Within IL, it ranks 299 of 1,548.
Learn more
the frost range explains how to read the range around Humboldt's dates instead of trusting one, and local microclimates explains what one yard in Humboldt can differ from the 61931 normal.