Kalispell, MT 59901 Frost Dates
When can you plant in Kalispell, MT?
Typically, the last spring freeze lands around 05/31, roughly 276 days out. The first fall frost typically arrives around 09/10, about 100 frost-free days later.
Zone 5b (-15 to -10°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 Kalispell, not a forecast for this year.
What to do before the first frost
About 2 weeks of growing season left in Kalispell before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 05/31 isn't a guarantee
05/31 is the middle of 30 years of NOAA records, not a promise. Plant by 05/13 and you're betting against frost in roughly 9 years out of 10. 06/22 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Kalispell compares
Kalispell's growing season runs about 100 days, ranking 39,705 of 40,283 US ZIP codes measured here, longest to shortest. Within MT, it ranks 306 of 392.
Learn more
the frost range covers how to read the range around Kalispell's dates instead of trusting one. local microclimates covers what one yard in Kalispell can differ from the 59901 normal.