South Heart, ND 58655 Frost Dates
58655, near South Heart, ND: the frost window
Typically, the last spring freeze lands around 05/18, roughly 263 days out. Fall's first freeze usually shows up around 09/25, roughly 129 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts South Heart 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
South Heart'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 South Heart's last frost
05/18 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/06 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.
South Heart against the rest of the dataset
South Heart's growing season runs about 129 days, ranking 38,493 of 40,283 US ZIP codes measured here, longest to shortest. Within ND, it ranks 313 of 405.
Learn more
Two guides worth reading on 58655: the frost range, on how to read the range around South Heart's dates instead of trusting one, and local microclimates, on what one yard in South Heart can differ from the 58655 normal.