Harmony, MN 55939 Frost Dates
When can you plant in Harmony, MN?
Typically, the last spring freeze lands around 05/14, roughly 259 days out. The first fall frost typically arrives around 09/28, about 136 frost-free days later.
Harmony 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
About 4 weeks of growing season left in Harmony before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
05/14 is the middle of 30 years of NOAA records, not a promise. Plant by 05/01 and you're betting against frost in roughly 9 years out of 10. 05/27 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Harmony compares
Harmony's growing season runs about 136 days, ranking 37,723 of 40,283 US ZIP codes measured here, longest to shortest. Within MN, it ranks 797 of 943.
Learn more
zone vs. frost date covers why Zone 4b and Harmony's frost date answer different questions. the frost range covers how to read the range around Harmony's dates instead of trusting one.