Rose City, MI 48621 Frost Dates
Frost dates for Rose City, MI, ZIP 48621
The last spring frost here typically falls around 05/20, about 265 days from today. The first fall frost typically arrives around 10/01, about 133 frost-free days later.
Rose City sits in USDA Zone 5a (-20 to -15°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 5a around Rose City 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.
How much risk comes with planting early here
05/20 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. 06/02 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Rose City compares
Rose City's growing season runs about 133 days, ranking 38,088 of 40,283 US ZIP codes measured here, longest to shortest. Within MI, it ranks 1,005 of 1,153.
Learn more
local microclimates explains what one yard in Rose City can differ from the 48621 normal, and zone vs. frost date explains why Zone 5a and Rose City's frost date answer different questions.