Wilton, ND 58521 Frost Dates
Frost dates for Wilton, ND, ZIP 58521
The last spring frost here typically falls around 05/11, about 256 days from today. The first fall frost typically arrives around 09/30, about 142 frost-free days later.
Wilton 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.
What to do before the first frost
Zone 4a around Wilton has about 5 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
How much risk comes with planting early here
05/11 is the middle of 30 years of NOAA records, not a promise. Plant by 04/30 and you're betting against frost in roughly 9 years out of 10. 05/25 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Wilton compares
Wilton's growing season runs about 142 days, ranking 36,780 of 40,283 US ZIP codes measured here, longest to shortest. Within ND, it ranks 109 of 405.
Learn more
zone vs. frost date explains why Zone 4a and Wilton's frost date answer different questions, and the frost range explains how to read the range around Wilton's dates instead of trusting one.