Porter, MN 56280 Frost Dates
Frost dates for Porter, MN, ZIP 56280
The last spring frost here typically falls around 05/02, about 247 days from today. The first fall frost typically arrives around 10/05, about 156 frost-free days later.
Zone 5a (-20 to -15°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 Porter, not a forecast for this year.
What to do before the first frost
Zone 5a around Porter 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 05/02 isn't a guarantee
05/02 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. 05/14 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Porter compares
About 156 days separate Porter's last and first frost, putting it 33,865 of 40,283 ZIP codes nationally. Within MN, it ranks 340 of 943.
Learn more
local microclimates explains what one yard in Porter can differ from the 56280 normal, and zone vs. frost date explains why Zone 5a and Porter's frost date answer different questions.