Ronan, MT 59863 Frost Dates
When can you plant in Ronan, MT?
The last spring frost here typically falls around 05/10, about 255 days from today. The first fall frost typically arrives around 10/05, about 147 frost-free days later.
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 Ronan, not a forecast for this year.
What to do before the first frost
About 5 weeks of growing season left in Ronan before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Ronan's last frost
05/10 is the middle of 30 years of NOAA records, not a promise. Plant by 04/27 and you're betting against frost in roughly 9 years out of 10. 05/26 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Ronan compares
About 147 days separate Ronan's last and first frost, putting it 35,915 of 40,283 ZIP codes nationally. Within MT, it ranks 32 of 392.
Learn more
zone vs. frost date covers why Zone 6a and Ronan's frost date answer different questions. the frost range covers how to read the range around Ronan's dates instead of trusting one.