Grand Forks, ND 58201 Frost Dates
When can you plant in Grand Forks, ND?
Around 05/10 is the usual last spring frost, about 255 days away. The first fall frost typically arrives around 10/01, about 144 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 Grand Forks, not a forecast for this year.
What to do before the first frost
About 5 weeks of growing season left in Grand Forks before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 05/10 isn't a guarantee
05/10 is the middle of 30 years of NOAA records, not a promise. Plant by 04/28 and you're betting against frost in roughly 9 years out of 10. 05/24 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Grand Forks compares
Grand Forks's growing season runs about 144 days, ranking 36,325 of 40,283 US ZIP codes measured here, longest to shortest. Within ND, it ranks 65 of 405.
Learn more
zone vs. frost date covers why Zone 4a and Grand Forks's frost date answer different questions. the frost range covers how to read the range around Grand Forks's dates instead of trusting one.