Monroe, MI 48161 Frost Dates
Frost dates for Monroe, MI, ZIP 48161
Around 04/23 is the usual last spring frost, about 238 days away. The first fall frost typically arrives around 10/23, about 182 frost-free days later.
The USDA Plant Hardiness Zone Map puts Monroe 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 Monroe 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 04/23 isn't a guarantee
04/23 is the middle of 30 years of NOAA records, not a promise. Plant by 04/08 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 Monroe compares
About 182 days separate Monroe's last and first frost, putting it 24,084 of 40,283 ZIP codes nationally. Within MI, it ranks 58 of 1,153.
Learn more
zone vs. frost date explains why Zone 6b and Monroe's frost date answer different questions, and the frost range explains how to read the range around Monroe's dates instead of trusting one.