Billings, MT 59006 Frost Dates
Billings, MT: when does the frost end?
Typically, the last spring freeze lands around 05/12, roughly 257 days out. Fall's first freeze usually shows up around 09/25, roughly 136 days after the last spring frost.
Billings sits in USDA Zone 4b (-25 to -20°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
With roughly 4 weeks until Billings's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 05/12 isn't a guarantee
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
At roughly 136 frost-free days, Billings places 37,610 of 40,283 ZIP codes in this dataset. Within MT, it ranks 81 of 392.
Learn more
Before leaning on 59006's figures: local microclimates explains what one yard in Billings can differ from the 59006 normal, while zone vs. frost date explains why Zone 4b and Billings's frost date answer different questions.