Columbia Falls, MT 59916 Frost Dates
When can you plant in Columbia Falls, MT?
The last spring frost here typically falls around 05/09, about 254 days from today. The first fall frost typically arrives around 10/01, about 141 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 5 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.
Why 05/09 isn't a guarantee
05/09 is the middle of 30 years of NOAA records, not a promise. Plant by 04/25 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 Columbia Falls compares
Columbia Falls's growing season runs about 141 days, ranking 36,900 of 40,283 US ZIP codes measured here, longest to shortest. Within MT, it ranks 60 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.