Rolla, ND 58367 Frost Dates
58367, near Rolla, ND: the frost window
The last spring frost here typically falls around 05/20, about 265 days from today. Fall's first freeze usually shows up around 09/26, roughly 128 days after the last spring frost.
Zone 3b (-35 to -30°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 Rolla, not a forecast for this year.
Stretching the season past the first frost
Rolla's growing season runs out in roughly 4 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around Rolla's last frost
05/20 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/08 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/31 and only about 1 year in 10 sees frost after that.
Rolla against the rest of the dataset
Rolla's growing season runs about 128 days, ranking 38,550 of 40,283 US ZIP codes measured here, longest to shortest. Within ND, it ranks 319 of 405.
Learn more
Two guides worth reading on 58367: local microclimates, on what one yard in Rolla can differ from the 58367 normal, and zone vs. frost date, on why Zone 3b and Rolla's frost date answer different questions.