Hillsdale, MI 49258 Frost Dates
Frost dates for Hillsdale, MI, ZIP 49258
Around 05/03 is the usual last spring frost, about 248 days away. The first fall frost typically arrives around 10/12, about 161 frost-free days later.
Zone 6a (-10 to -5°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Hillsdale, not a forecast for this year.
What to do before the first frost
Zone 6a around Hillsdale has about 6 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 05/03 isn't a guarantee
05/03 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. 05/19 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Hillsdale compares
About 161 days separate Hillsdale's last and first frost, putting it 32,009 of 40,283 ZIP codes nationally. Within MI, it ranks 562 of 1,153.
Learn more
local microclimates explains what one yard in Hillsdale can differ from the 49258 normal, and zone vs. frost date explains why Zone 6a and Hillsdale's frost date answer different questions.