Hamilton, ND 58238 Frost Dates
Frost dates for Hamilton, ND, ZIP 58238
Around 05/12 is the usual last spring frost, about 257 days away. The first fall frost typically arrives around 09/30, about 139 frost-free days later.
The USDA Plant Hardiness Zone Map puts Hamilton in Zone 4a (-30 to -25°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 4a around Hamilton 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
05/12 is the middle of 30 years of NOAA records, not a promise. Plant by 04/29 and you're betting against frost in roughly 9 years out of 10. 05/27 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Hamilton compares
Hamilton's growing season runs about 139 days, ranking 37,327 of 40,283 US ZIP codes measured here, longest to shortest. Within ND, it ranks 176 of 405.
Learn more
the frost range explains how to read the range around Hamilton's dates instead of trusting one, and local microclimates explains what one yard in Hamilton can differ from the 58238 normal.