FrostDateCheck

Mora, MN 55051 Frost Dates

Frost dates for Mora, MN, ZIP 55051

Zone 4a

Typically, the last spring freeze lands around 05/09, roughly 254 days out. The first fall frost typically arrives around 09/30, about 142 frost-free days later.

The USDA Plant Hardiness Zone Map puts Mora in Zone 4a (-30 to -25°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.

What to do before the first frost

Zone 4a around Mora 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

05/09 is the middle of 30 years of NOAA records, not a promise. Plant by 04/26 and you're betting against frost in roughly 9 years out of 10. 05/26 is the safer bet, historically only a 1-in-10 chance of frost that late.

How Mora compares

Mora's growing season runs about 142 days, ranking 36,734 of 40,283 US ZIP codes measured here, longest to shortest. Within MN, it ranks 691 of 943.

Learn more

zone vs. frost date explains why Zone 4a and Mora's frost date answer different questions, and the frost range explains how to read the range around Mora's dates instead of trusting one.