Medicine Lake, MT 59219 Frost Dates
59219, near Medicine Lake, MT: the frost window
Typically, the last spring freeze lands around 05/16, roughly 261 days out. Fall's first freeze usually shows up around 09/18, roughly 125 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Medicine Lake in Zone 3b (-35 to -30°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
Medicine Lake's growing season runs out in roughly 3 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
05/16 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/04 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/30 and only about 1 year in 10 sees frost after that.
Medicine Lake against the rest of the dataset
At roughly 125 frost-free days, Medicine Lake places 38,807 of 40,283 ZIP codes in this dataset. Within MT, it ranks 175 of 392.
Learn more
Two guides worth reading on 59219: local microclimates, on what one yard in Medicine Lake can differ from the 59219 normal, and zone vs. frost date, on why Zone 3b and Medicine Lake's frost date answer different questions.