Columbus, MT 59069 Frost Dates
Frost dates for Columbus, MT, ZIP 59069
The last spring frost here typically falls around 05/27, about 272 days from today. The first fall frost typically arrives around 09/14, about 108 frost-free days later.
The USDA Plant Hardiness Zone Map puts Columbus in Zone 5a (-20 to -15°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 5a around Columbus has about 2 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 05/27 isn't a guarantee
05/27 is the middle of 30 years of NOAA records, not a promise. Plant by 05/14 and you're betting against frost in roughly 9 years out of 10. 06/12 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Columbus compares
Columbus's growing season runs about 108 days, ranking 39,540 of 40,283 US ZIP codes measured here, longest to shortest. Within MT, it ranks 282 of 392.
Learn more
zone vs. frost date explains why Zone 5a and Columbus's frost date answer different questions, and the frost range explains how to read the range around Columbus's dates instead of trusting one.