Saco, MT 59241 Frost Dates
Frost dates for Saco, MT, ZIP 59241
The last spring frost here typically falls around 05/15, about 260 days from today. The first fall frost typically arrives around 09/26, about 132 frost-free days later.
Saco sits in USDA Zone 3b (-35 to -30°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 3b around Saco 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 05/15 isn't a guarantee
05/15 is the middle of 30 years of NOAA records, not a promise. Plant by 05/03 and you're betting against frost in roughly 9 years out of 10. 05/30 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Saco compares
About 132 days separate Saco's last and first frost, putting it 38,233 of 40,283 ZIP codes nationally. Within MT, it ranks 127 of 392.
Learn more
the frost range explains how to read the range around Saco's dates instead of trusting one, and local microclimates explains what one yard in Saco can differ from the 59241 normal.