Hardin, MT 59022 Frost Dates
Hardin, MT: when does the frost end?
Around 05/13 is the usual last spring frost, about 258 days away. Fall's first freeze usually shows up around 09/29, roughly 135 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 Hardin, not a forecast for this year.
Stretching the season past the first frost
With roughly 5 weeks until Hardin's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Hardin's last frost
05/13 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.
Hardin against the rest of the dataset
About 135 days separate Hardin's last and first frost, putting it 37,859 of 40,283 ZIP codes nationally. Within MT, it ranks 98 of 392.
Learn more
Before leaning on 59022's figures: zone vs. frost date explains why Zone 4b and Hardin's frost date answer different questions, while the frost range explains how to read the range around Hardin's dates instead of trusting one.