Fairfield, MT 59410 Frost Dates
When can you plant in Fairfield, MT?
Typically, the last spring freeze lands around 05/19, roughly 264 days out. The first fall frost typically arrives around 09/21, about 125 frost-free days later.
Zone 4b (-25 to -20°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 Fairfield, not a forecast for this year.
What to do before the first frost
About 3 weeks of growing season left in Fairfield before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Fairfield's last frost
05/19 is the middle of 30 years of NOAA records, not a promise. Plant by 05/04 and you're betting against frost in roughly 9 years out of 10. 05/31 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Fairfield compares
Fairfield's growing season runs about 125 days, ranking 38,783 of 40,283 US ZIP codes measured here, longest to shortest. Within MT, it ranks 174 of 392.
Learn more
the frost range covers how to read the range around Fairfield's dates instead of trusting one. local microclimates covers what one yard in Fairfield can differ from the 59410 normal.