Winifred, MT 59451 Frost Dates
Winifred, MT: when does the frost end?
Around 05/16 is the usual last spring frost, about 261 days away. Fall's first freeze usually shows up around 09/23, roughly 127 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Winifred in Zone 4b (-25 to -20°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
With roughly 4 weeks until Winifred'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
05/16 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 05/30 and only about 1 year in 10 sees frost after that.
Winifred against the rest of the dataset
About 127 days separate Winifred's last and first frost, putting it 38,665 of 40,283 ZIP codes nationally. Within MT, it ranks 156 of 392.
Learn more
Before leaning on 59451's figures: zone vs. frost date explains why Zone 4b and Winifred's frost date answer different questions, while the frost range explains how to read the range around Winifred's dates instead of trusting one.