Stanford, MT 59479 Frost Dates
Frost dates for Stanford, MT, ZIP 59479
Typically, the last spring freeze lands around 05/25, roughly 270 days out. The first fall frost typically arrives around 09/21, about 118 frost-free days later.
Stanford sits in USDA Zone 4b (-25 to -20°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 4b around Stanford 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.
Why 05/25 isn't a guarantee
05/25 is the middle of 30 years of NOAA records, not a promise. Plant by 05/10 and you're betting against frost in roughly 9 years out of 10. 06/15 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Stanford compares
At roughly 118 frost-free days, Stanford places 39,226 of 40,283 ZIP codes in this dataset. Within MT, it ranks 234 of 392.
Learn more
zone vs. frost date explains why Zone 4b and Stanford's frost date answer different questions, and the frost range explains how to read the range around Stanford's dates instead of trusting one.