Columbia Falls, MT 59912 Frost Dates
When can you plant in Columbia Falls, MT?
Around 05/16 is the usual last spring frost, about 261 days away. The first fall frost typically arrives around 09/25, about 129 frost-free days later.
Columbia Falls 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 4 weeks of growing season left in Columbia Falls 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
05/16 is the middle of 30 years of NOAA records, not a promise. Plant by 05/02 and you're betting against frost in roughly 9 years out of 10. 06/06 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Columbia Falls compares
At roughly 129 frost-free days, Columbia Falls places 38,455 of 40,283 ZIP codes in this dataset. Within MT, it ranks 135 of 392.
Learn more
zone vs. frost date covers why Zone 5a and Columbia Falls's frost date answer different questions. the frost range covers how to read the range around Columbia Falls's dates instead of trusting one.