Kulm, ND 58456 Frost Dates
58456, near Kulm, ND: the frost window
Typically, the last spring freeze lands around 05/07, roughly 252 days out. Fall's first freeze usually shows up around 10/02, roughly 148 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Kulm in Zone 4b (-25 to -20°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
Kulm's growing season runs out in roughly 5 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 05/07 isn't a guarantee
05/07 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/24 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/20 and only about 1 year in 10 sees frost after that.
Kulm against the rest of the dataset
At roughly 148 frost-free days, Kulm places 35,792 of 40,283 ZIP codes in this dataset. Within ND, it ranks 45 of 405.
Learn more
Two guides worth reading on 58456: local microclimates, on what one yard in Kulm can differ from the 58456 normal, and zone vs. frost date, on why Zone 4b and Kulm's frost date answer different questions.