Butte-Silver Bow, MT 59750 Frost Dates
When can you plant in Butte-Silver Bow, MT?
Around 06/13 is the usual last spring frost, about 289 days away. The first fall frost typically arrives around 09/05, about 83 frost-free days later.
Butte-Silver Bow sits in USDA Zone 5a (-20 to -15°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
About 1 week of growing season left in Butte-Silver Bow before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
06/13 is the middle of 30 years of NOAA records, not a promise. Plant by 05/27 and you're betting against frost in roughly 9 years out of 10. 07/01 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Butte-Silver Bow compares
About 83 days separate Butte-Silver Bow's last and first frost, putting it 40,014 of 40,283 ZIP codes nationally. Within MT, it ranks 355 of 392.
Learn more
zone vs. frost date covers why Zone 5a and Butte-Silver Bow's frost date answer different questions. the frost range covers how to read the range around Butte-Silver Bow's dates instead of trusting one.