Killdeer, ND 58640 Frost Dates
58640, near Killdeer, ND: the frost window
Typically, the last spring freeze lands around 05/21, roughly 266 days out. Fall's first freeze usually shows up around 09/23, roughly 124 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Killdeer in Zone 4a (-30 to -25°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
Killdeer'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.
How much risk comes with planting early here
05/21 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/09 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/05 and only about 1 year in 10 sees frost after that.
Killdeer against the rest of the dataset
Killdeer's growing season runs about 124 days, ranking 38,853 of 40,283 US ZIP codes measured here, longest to shortest. Within ND, it ranks 365 of 405.
Learn more
Two guides worth reading on 58640: the frost range, on how to read the range around Killdeer's dates instead of trusting one, and local microclimates, on what one yard in Killdeer can differ from the 58640 normal.