Columbus, MT 59001 Frost Dates
When can you plant in Columbus, MT?
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.
Zone 5a (-20 to -15°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Columbus, not a forecast for this year.
What to do before the first frost
About 2 weeks of growing season left in Columbus 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
05/27 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
About 108 days separate Columbus's last and first frost, putting it 39,538 of 40,283 ZIP codes nationally. Within MT, it ranks 280 of 392.
Learn more
local microclimates covers what one yard in Columbus can differ from the 59001 normal. zone vs. frost date covers why Zone 5a and Columbus's frost date answer different questions.