Polson, MT 59914 Frost Dates
When can you plant in Polson, MT?
Typically, the last spring freeze lands around 05/01, roughly 246 days out. The first fall frost typically arrives around 10/15, about 165 frost-free days later.
The USDA Plant Hardiness Zone Map puts Polson in Zone 6a (-10 to -5°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
About 7 weeks of growing season left in Polson 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
05/01 is the middle of 30 years of NOAA records, not a promise. Plant by 04/16 and you're betting against frost in roughly 9 years out of 10. 05/16 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Polson compares
Polson's growing season runs about 165 days, ranking 30,535 of 40,283 US ZIP codes measured here, longest to shortest. Within MT, it ranks 3 of 392.
Learn more
local microclimates covers what one yard in Polson can differ from the 59914 normal. zone vs. frost date covers why Zone 6a and Polson's frost date answer different questions.