Hardin, MT 59010 Frost Dates
Frost dates for Hardin, MT, ZIP 59010
Around 05/26 is the usual last spring frost, about 271 days away. The first fall frost typically arrives around 09/16, about 111 frost-free days later.
The USDA Plant Hardiness Zone Map puts Hardin 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 Hardin has about 3 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
05/26 is the middle of 30 years of NOAA records, not a promise. Plant by 05/12 and you're betting against frost in roughly 9 years out of 10. 06/13 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Hardin compares
About 111 days separate Hardin's last and first frost, putting it 39,454 of 40,283 ZIP codes nationally. Within MT, it ranks 267 of 392.
Learn more
the frost range explains how to read the range around Hardin's dates instead of trusting one, and local microclimates explains what one yard in Hardin can differ from the 59010 normal.