Cascade, MT 59403 Frost Dates
When can you plant in Cascade, MT?
Around 05/12 is the usual last spring frost, about 257 days away. The first fall frost typically arrives around 09/28, about 138 frost-free days later.
The USDA Plant Hardiness Zone Map puts Cascade in Zone 4b (-25 to -20°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 4 weeks of growing season left in Cascade before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Cascade's last frost
05/12 is the middle of 30 years of NOAA records, not a promise. Plant by 04/30 and you're betting against frost in roughly 9 years out of 10. 05/27 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Cascade compares
About 138 days separate Cascade's last and first frost, putting it 37,441 of 40,283 ZIP codes nationally. Within MT, it ranks 74 of 392.
Learn more
local microclimates covers what one yard in Cascade can differ from the 59403 normal. zone vs. frost date covers why Zone 4b and Cascade's frost date answer different questions.