Belt, MT 59480 Frost Dates
Frost dates for Belt, MT, ZIP 59480
Around 06/06 is the usual last spring frost, about 282 days away. The first fall frost typically arrives around 09/12, about 99 frost-free days later.
The USDA Plant Hardiness Zone Map puts Belt 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 Belt has about 2 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.
The actual range around Belt's last frost
06/06 is the middle of 30 years of NOAA records, not a promise. Plant by 05/23 and you're betting against frost in roughly 9 years out of 10. 06/28 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Belt compares
At roughly 99 frost-free days, Belt places 39,737 of 40,283 ZIP codes in this dataset. Within MT, it ranks 315 of 392.
Learn more
the frost range explains how to read the range around Belt's dates instead of trusting one, and local microclimates explains what one yard in Belt can differ from the 59480 normal.