Billings, MT 59112 Frost Dates
59112, near Billings, MT: the frost window
The last spring frost here typically falls around 05/12, about 257 days from today. Fall's first freeze usually shows up around 09/25, roughly 136 days after the last spring frost.
Zone 5a (-20 to -15°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 Billings, not a forecast for this year.
Stretching the season past the first frost
Billings'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 05/26 and only about 1 year in 10 sees frost after that.
Billings against the rest of the dataset
About 136 days separate Billings's last and first frost, putting it 37,617 of 40,283 ZIP codes nationally. Within MT, it ranks 88 of 392.
Learn more
Two guides worth reading on 59112: zone vs. frost date, on why Zone 5a and Billings's frost date answer different questions, and the frost range, on how to read the range around Billings's dates instead of trusting one.