Arthur, ND 58006 Frost Dates
58006, near Arthur, ND: the frost window
Around 05/09 is the usual last spring frost, about 254 days away. Fall's first freeze usually shows up around 10/01, roughly 143 days after the last spring frost.
Arthur sits in USDA Zone 4a (-30 to -25°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
Arthur'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 05/09 isn't a guarantee
05/09 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/25 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/21 and only about 1 year in 10 sees frost after that.
Arthur against the rest of the dataset
About 143 days separate Arthur's last and first frost, putting it 36,617 of 40,283 ZIP codes nationally. Within ND, it ranks 93 of 405.
Learn more
Two guides worth reading on 58006: zone vs. frost date, on why Zone 4a and Arthur's frost date answer different questions, and the frost range, on how to read the range around Arthur's dates instead of trusting one.