Forbes, ND 58439 Frost Dates
Frost dates for Forbes, ND, ZIP 58439
The last spring frost here typically falls around 05/09, about 254 days from today. The first fall frost typically arrives around 09/28, about 141 frost-free days later.
The USDA Plant Hardiness Zone Map puts Forbes in Zone 4b (-25 to -20°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 4b around Forbes has about 4 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 05/09 isn't a guarantee
05/09 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. 05/21 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Forbes compares
At roughly 141 frost-free days, Forbes places 37,016 of 40,283 ZIP codes in this dataset. Within ND, it ranks 121 of 405.
Learn more
the frost range explains how to read the range around Forbes's dates instead of trusting one, and local microclimates explains what one yard in Forbes can differ from the 58439 normal.