Jordan, MT 59077 Frost Dates
59077, near Jordan, MT: the frost window
Around 05/05 is the usual last spring frost, about 250 days away. Fall's first freeze usually shows up around 10/04, roughly 151 days after the last spring frost.
Zone 4b (-25 to -20°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Jordan, not a forecast for this year.
Stretching the season past the first frost
Jordan'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.
How much risk comes with planting early here
05/05 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/20 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/26 and only about 1 year in 10 sees frost after that.
Jordan against the rest of the dataset
Jordan's growing season runs about 151 days, ranking 35,153 of 40,283 US ZIP codes measured here, longest to shortest. Within MT, it ranks 20 of 392.
Learn more
Two guides worth reading on 59077: zone vs. frost date, on why Zone 4b and Jordan's frost date answer different questions, and the frost range, on how to read the range around Jordan's dates instead of trusting one.