Corunna, MI 48817 Frost Dates
Frost dates for Corunna, MI, ZIP 48817
Around 05/05 is the usual last spring frost, about 250 days away. The first fall frost typically arrives around 10/14, about 160 frost-free days later.
The USDA Plant Hardiness Zone Map puts Corunna 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 Corunna 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.
How much risk comes with planting early here
05/05 is the middle of 30 years of NOAA records, not a promise. Plant by 04/20 and you're betting against frost in roughly 9 years out of 10. 05/20 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Corunna compares
Corunna's growing season runs about 160 days, ranking 32,326 of 40,283 US ZIP codes measured here, longest to shortest. Within MI, it ranks 631 of 1,153.
Learn more
zone vs. frost date explains why Zone 6a and Corunna's frost date answer different questions, and the frost range explains how to read the range around Corunna's dates instead of trusting one.