Terry, MT 59349 Frost Dates
59349, near Terry, MT: the frost window
Around 05/12 is the usual last spring frost, about 257 days away. Fall's first freeze usually shows up around 09/28, roughly 137 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Terry in Zone 4a (-30 to -25°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
Terry's growing season runs out in roughly 4 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
05/12 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/30 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/25 and only about 1 year in 10 sees frost after that.
Terry against the rest of the dataset
Terry's growing season runs about 137 days, ranking 37,561 of 40,283 US ZIP codes measured here, longest to shortest. Within MT, it ranks 79 of 392.
Learn more
Two guides worth reading on 59349: local microclimates, on what one yard in Terry can differ from the 59349 normal, and zone vs. frost date, on why Zone 4a and Terry's frost date answer different questions.