Mount Morris, MI 48437 Frost Dates
Frost dates for Mount Morris, MI, ZIP 48437
The last spring frost here typically falls around 05/08, about 253 days from today. The first fall frost typically arrives around 10/05, about 148 frost-free days later.
Mount Morris sits in USDA Zone 6a (-10 to -5°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
Zone 6a around Mount Morris has about 5 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 05/08 isn't a guarantee
05/08 is the middle of 30 years of NOAA records, not a promise. Plant by 04/28 and you're betting against frost in roughly 9 years out of 10. 05/22 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Mount Morris compares
Mount Morris's growing season runs about 148 days, ranking 35,719 of 40,283 US ZIP codes measured here, longest to shortest. Within MI, it ranks 837 of 1,153.
Learn more
zone vs. frost date explains why Zone 6a and Mount Morris's frost date answer different questions, and the frost range explains how to read the range around Mount Morris's dates instead of trusting one.