Glendive, MT 59330 Frost Dates
59330, near Glendive, MT: the frost window
Typically, the last spring freeze lands around 05/03, roughly 248 days out. Fall's first freeze usually shows up around 10/04, roughly 153 days after the last spring frost.
Glendive sits in USDA Zone 4a (-30 to -25°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
Glendive'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.
Why 05/03 isn't a guarantee
05/03 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/19 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/16 and only about 1 year in 10 sees frost after that.
Glendive against the rest of the dataset
About 153 days separate Glendive's last and first frost, putting it 34,530 of 40,283 ZIP codes nationally. Within MT, it ranks 12 of 392.
Learn more
Two guides worth reading on 59330: zone vs. frost date, on why Zone 4a and Glendive's frost date answer different questions, and the frost range, on how to read the range around Glendive's dates instead of trusting one.