Marion, ND 58466 Frost Dates
58466, near Marion, ND: the frost window
Around 05/10 is the usual last spring frost, about 255 days away. Fall's first freeze usually shows up around 09/28, roughly 140 days after the last spring frost.
Marion 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.
Stretching the season past the first frost
Marion'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.
Why 05/10 isn't a guarantee
05/10 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/28 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/22 and only about 1 year in 10 sees frost after that.
Marion against the rest of the dataset
At roughly 140 frost-free days, Marion places 37,192 of 40,283 ZIP codes in this dataset. Within ND, it ranks 129 of 405.
Learn more
Two guides worth reading on 58466: the frost range, on how to read the range around Marion's dates instead of trusting one, and local microclimates, on what one yard in Marion can differ from the 58466 normal.