Winnett, MT 59058 Frost Dates
Winnett, MT: when does the frost end?
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.
Winnett 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 5 weeks until Winnett's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
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.
Winnett against the rest of the dataset
Winnett's growing season runs about 151 days, ranking 35,179 of 40,283 US ZIP codes measured here, longest to shortest. Within MT, it ranks 21 of 392.
Learn more
Before leaning on 59058's figures: local microclimates explains what one yard in Winnett can differ from the 59058 normal, while zone vs. frost date explains why Zone 4b and Winnett's frost date answer different questions.