Mercer, ND 58559 Frost Dates
When can you plant in Mercer, ND?
The last spring frost here typically falls around 05/14, about 259 days from today. The first fall frost typically arrives around 09/26, about 136 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 Mercer, not a forecast for this year.
What to do before the first frost
About 4 weeks of growing season left in Mercer before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 05/14 isn't a guarantee
05/14 is the middle of 30 years of NOAA records, not a promise. Plant by 05/03 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 Mercer compares
About 136 days separate Mercer's last and first frost, putting it 37,802 of 40,283 ZIP codes nationally. Within ND, it ranks 245 of 405.
Learn more
zone vs. frost date covers why Zone 4a and Mercer's frost date answer different questions. the frost range covers how to read the range around Mercer's dates instead of trusting one.