Bozeman, MT 59772 Frost Dates
Bozeman, MT: when does the frost end?
Around 05/26 is the usual last spring frost, about 271 days away. Fall's first freeze usually shows up around 09/22, roughly 116 days after the last spring frost.
Zone 5a (-20 to -15°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 Bozeman, not a forecast for this year.
Stretching the season past the first frost
With roughly 4 weeks until Bozeman's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
05/26 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/09 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/14 and only about 1 year in 10 sees frost after that.
Bozeman against the rest of the dataset
About 116 days separate Bozeman's last and first frost, putting it 39,272 of 40,283 ZIP codes nationally. Within MT, it ranks 240 of 392.
Learn more
Before leaning on 59772's figures: local microclimates explains what one yard in Bozeman can differ from the 59772 normal, while zone vs. frost date explains why Zone 5a and Bozeman's frost date answer different questions.