Melstone, MT 59054 Frost Dates
59054, near Melstone, MT: the frost window
Around 05/10 is the usual last spring frost, about 255 days away. Fall's first freeze usually shows up around 09/29, roughly 141 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Melstone in Zone 4b (-25 to -20°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
Melstone's growing season runs out in roughly 5 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
The actual range around Melstone's last frost
05/10 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/28 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/23 and only about 1 year in 10 sees frost after that.
Melstone against the rest of the dataset
At roughly 141 frost-free days, Melstone places 37,003 of 40,283 ZIP codes in this dataset. Within MT, it ranks 66 of 392.
Learn more
Two guides worth reading on 59054: local microclimates, on what one yard in Melstone can differ from the 59054 normal, and zone vs. frost date, on why Zone 4b and Melstone's frost date answer different questions.