Harrietta, MI 49618 Frost Dates
Frost dates for Harrietta, MI, ZIP 49618
Typically, the last spring freeze lands around 05/19, roughly 264 days out. The first fall frost typically arrives around 10/01, about 135 frost-free days later.
The USDA Plant Hardiness Zone Map puts Harrietta in Zone 5a (-20 to -15°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 5a around Harrietta 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.
The actual range around Harrietta's last frost
05/19 is the middle of 30 years of NOAA records, not a promise. Plant by 05/02 and you're betting against frost in roughly 9 years out of 10. 06/03 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Harrietta compares
About 135 days separate Harrietta's last and first frost, putting it 37,928 of 40,283 ZIP codes nationally. Within MI, it ranks 985 of 1,153.
Learn more
local microclimates explains what one yard in Harrietta can differ from the 49618 normal, and zone vs. frost date explains why Zone 5a and Harrietta's frost date answer different questions.