Deer Lodge, MT 59728 Frost Dates
When can you plant in Deer Lodge, MT?
Typically, the last spring freeze lands around 06/09, roughly 285 days out. The first fall frost typically arrives around 09/08, about 91 frost-free days later.
Deer Lodge sits in USDA Zone 4b (-25 to -20°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 2 weeks of growing season left in Deer Lodge before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 06/09 isn't a guarantee
06/09 is the middle of 30 years of NOAA records, not a promise. Plant by 05/23 and you're betting against frost in roughly 9 years out of 10. 06/26 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Deer Lodge compares
Deer Lodge's growing season runs about 91 days, ranking 39,897 of 40,283 US ZIP codes measured here, longest to shortest. Within MT, it ranks 334 of 392.
Learn more
zone vs. frost date covers why Zone 4b and Deer Lodge's frost date answer different questions. the frost range covers how to read the range around Deer Lodge's dates instead of trusting one.