Three Forks, MT 59752 Frost Dates
Three Forks, MT: when does the frost end?
The last spring frost here typically falls around 05/09, about 254 days from today. Fall's first freeze usually shows up around 09/27, roughly 139 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Three Forks in Zone 5a (-20 to -15°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
With roughly 4 weeks until Three Forks'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
05/09 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/29 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/24 and only about 1 year in 10 sees frost after that.
Three Forks against the rest of the dataset
About 139 days separate Three Forks's last and first frost, putting it 37,235 of 40,283 ZIP codes nationally. Within MT, it ranks 68 of 392.
Learn more
Before leaning on 59752's figures: local microclimates explains what one yard in Three Forks can differ from the 59752 normal, while zone vs. frost date explains why Zone 5a and Three Forks's frost date answer different questions.