Mason, IL 62443 Frost Dates
Frost dates for Mason, IL, ZIP 62443
Typically, the last spring freeze lands around 04/03, roughly 218 days out. The first fall frost typically arrives around 10/24, about 202 frost-free days later.
The USDA Plant Hardiness Zone Map puts Mason in Zone 6b (-5 to 0°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 6b around Mason 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 Mason's last frost
04/03 is the middle of 30 years of NOAA records, not a promise. Plant by 03/19 and you're betting against frost in roughly 9 years out of 10. 04/25 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Mason compares
Mason's growing season runs about 202 days, ranking 17,348 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 187 of 1,548.
Learn more
the frost range explains how to read the range around Mason's dates instead of trusting one, and local microclimates explains what one yard in Mason can differ from the 62443 normal.