Lima, MT 59739 Frost Dates
Lima, MT: when does the frost end?
Around 06/11 is the usual last spring frost, about 287 days away. Fall's first freeze usually shows up around 09/10, roughly 89 days after the last spring frost.
Lima sits in USDA Zone 5a (-20 to -15°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 2 weeks until Lima's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Lima's last frost
06/11 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/24 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/30 and only about 1 year in 10 sees frost after that.
Lima against the rest of the dataset
At roughly 89 frost-free days, Lima places 39,935 of 40,283 ZIP codes in this dataset. Within MT, it ranks 340 of 392.
Learn more
Before leaning on 59739's figures: zone vs. frost date explains why Zone 5a and Lima's frost date answer different questions, while the frost range explains how to read the range around Lima's dates instead of trusting one.