Richey, MT 59315 Frost Dates
Frost dates for Richey, MT, ZIP 59315
Typically, the last spring freeze lands around 05/03, roughly 248 days out. The first fall frost typically arrives around 10/04, about 153 frost-free days later.
Richey sits in USDA Zone 4a (-30 to -25°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.
What to do before the first frost
Zone 4a around Richey has about 5 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
The actual range around Richey's last frost
05/03 is the middle of 30 years of NOAA records, not a promise. Plant by 04/19 and you're betting against frost in roughly 9 years out of 10. 05/16 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Richey compares
At roughly 153 frost-free days, Richey places 34,647 of 40,283 ZIP codes in this dataset. Within MT, it ranks 13 of 392.
Learn more
local microclimates explains what one yard in Richey can differ from the 59315 normal, and zone vs. frost date explains why Zone 4a and Richey's frost date answer different questions.