Thompson, ND 58278 Frost Dates
Frost dates for Thompson, ND, ZIP 58278
Typically, the last spring freeze lands around 05/10, roughly 255 days out. The first fall frost typically arrives around 10/01, about 144 frost-free days later.
Thompson 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 Thompson 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.
Why 05/10 isn't a guarantee
05/10 is the middle of 30 years of NOAA records, not a promise. Plant by 04/28 and you're betting against frost in roughly 9 years out of 10. 05/24 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Thompson compares
About 144 days separate Thompson's last and first frost, putting it 36,403 of 40,283 ZIP codes nationally. Within ND, it ranks 72 of 405.
Learn more
zone vs. frost date explains why Zone 4a and Thompson's frost date answer different questions, and the frost range explains how to read the range around Thompson's dates instead of trusting one.