Belt, MT 59472 Frost Dates
Belt, MT: when does the frost end?
Around 05/06 is the usual last spring frost, about 251 days away. Fall's first freeze usually shows up around 10/01, roughly 147 days after the last spring frost.
Belt 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.
Stretching the season past the first frost
With roughly 5 weeks until Belt'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
05/06 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/23 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/19 and only about 1 year in 10 sees frost after that.
Belt against the rest of the dataset
Belt's growing season runs about 147 days, ranking 35,958 of 40,283 US ZIP codes measured here, longest to shortest. Within MT, it ranks 34 of 392.
Learn more
Before leaning on 59472's figures: zone vs. frost date explains why Zone 4b and Belt's frost date answer different questions, while the frost range explains how to read the range around Belt's dates instead of trusting one.