Casselton, ND 58121 Frost Dates
Casselton, ND: when does the frost end?
Typically, the last spring freeze lands around 05/09, roughly 254 days out. Fall's first freeze usually shows up around 10/01, roughly 143 days after the last spring frost.
Casselton 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
With roughly 5 weeks until Casselton's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
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.
Casselton against the rest of the dataset
Casselton's growing season runs about 143 days, ranking 36,540 of 40,283 US ZIP codes measured here, longest to shortest. Within ND, it ranks 83 of 405.
Learn more
Before leaning on 58121's figures: zone vs. frost date explains why Zone 4a and Casselton's frost date answer different questions, while the frost range explains how to read the range around Casselton's dates instead of trusting one.