Miles City, MT 59333 Frost Dates
When can you plant in Miles City, MT?
Around 05/08 is the usual last spring frost, about 253 days away. The first fall frost typically arrives around 09/30, about 144 frost-free days later.
Miles City sits in USDA Zone 4a (-30 to -25°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 Miles City before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 05/08 isn't a guarantee
05/08 is the middle of 30 years of NOAA records, not a promise. Plant by 04/26 and you're betting against frost in roughly 9 years out of 10. 05/21 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Miles City compares
Miles City's growing season runs about 144 days, ranking 36,354 of 40,283 US ZIP codes measured here, longest to shortest. Within MT, it ranks 37 of 392.
Learn more
the frost range covers how to read the range around Miles City's dates instead of trusting one. local microclimates covers what one yard in Miles City can differ from the 59333 normal.