Malta, MT 59537 Frost Dates
59537, near Malta, MT: the frost window
Around 05/19 is the usual last spring frost, about 264 days away. Fall's first freeze usually shows up around 09/22, roughly 124 days after the last spring frost.
Malta sits in USDA Zone 3b (-35 to -30°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
Malta'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.
The actual range around Malta's last frost
05/19 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/05 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/02 and only about 1 year in 10 sees frost after that.
Malta against the rest of the dataset
About 124 days separate Malta's last and first frost, putting it 38,844 of 40,283 ZIP codes nationally. Within MT, it ranks 186 of 392.
Learn more
Two guides worth reading on 59537: the frost range, on how to read the range around Malta's dates instead of trusting one, and local microclimates, on what one yard in Malta can differ from the 59537 normal.