Thompson Falls, MT 59874 Frost Dates
Thompson Falls, MT: when does the frost end?
The last spring frost here typically falls around 05/20, about 265 days from today. Fall's first freeze usually shows up around 09/21, roughly 122 days after the last spring frost.
Zone 6a (-10 to -5°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 Thompson Falls, not a forecast for this year.
Stretching the season past the first frost
With roughly 3 weeks until Thompson Falls's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Thompson Falls's last frost
05/20 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 06/09 and only about 1 year in 10 sees frost after that.
Thompson Falls against the rest of the dataset
About 122 days separate Thompson Falls's last and first frost, putting it 38,949 of 40,283 ZIP codes nationally. Within MT, it ranks 204 of 392.
Learn more
Before leaning on 59874's figures: the frost range explains how to read the range around Thompson Falls's dates instead of trusting one, while local microclimates explains what one yard in Thompson Falls can differ from the 59874 normal.