Halstad, MN 56548 Frost Dates
Frost dates for Halstad, MN, ZIP 56548
Around 05/11 is the usual last spring frost, about 256 days away. The first fall frost typically arrives around 09/27, about 137 frost-free days later.
Zone 4a (-30 to -25°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 Halstad, not a forecast for this year.
What to do before the first frost
Zone 4a around Halstad has about 4 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 05/11 isn't a guarantee
05/11 is the middle of 30 years of NOAA records, not a promise. Plant by 04/30 and you're betting against frost in roughly 9 years out of 10. 05/25 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Halstad compares
Halstad's growing season runs about 137 days, ranking 37,562 of 40,283 US ZIP codes measured here, longest to shortest. Within MN, it ranks 784 of 943.
Learn more
local microclimates explains what one yard in Halstad can differ from the 56548 normal, and zone vs. frost date explains why Zone 4a and Halstad's frost date answer different questions.