La Prairie, IL 62346 Frost Dates
Frost dates for La Prairie, IL, ZIP 62346
Around 04/18 is the usual last spring frost, about 233 days away. The first fall frost typically arrives around 10/21, about 187 frost-free days later.
The USDA Plant Hardiness Zone Map puts La Prairie in Zone 6a (-10 to -5°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 6a around La Prairie 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.
Why 04/18 isn't a guarantee
04/18 is the middle of 30 years of NOAA records, not a promise. Plant by 04/03 and you're betting against frost in roughly 9 years out of 10. 05/01 is the safer bet, historically only a 1-in-10 chance of frost that late.
How La Prairie compares
About 187 days separate La Prairie's last and first frost, putting it 22,650 of 40,283 ZIP codes nationally. Within IL, it ranks 812 of 1,548.
Learn more
local microclimates explains what one yard in La Prairie can differ from the 62346 normal, and zone vs. frost date explains why Zone 6a and La Prairie's frost date answer different questions.