Granite Falls, MN 56241 Frost Dates
Frost dates for Granite Falls, MN, ZIP 56241
The last spring frost here typically falls around 05/04, about 249 days from today. The first fall frost typically arrives around 10/01, about 150 frost-free days later.
Granite Falls sits in USDA Zone 4b (-25 to -20°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 4b around Granite Falls 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 05/04 isn't a guarantee
05/04 is the middle of 30 years of NOAA records, not a promise. Plant by 04/21 and you're betting against frost in roughly 9 years out of 10. 05/18 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Granite Falls compares
About 150 days separate Granite Falls's last and first frost, putting it 35,299 of 40,283 ZIP codes nationally. Within MN, it ranks 517 of 943.
Learn more
local microclimates explains what one yard in Granite Falls can differ from the 56241 normal, and zone vs. frost date explains why Zone 4b and Granite Falls's frost date answer different questions.