Whitehall, MT 59759 Frost Dates
Frost dates for Whitehall, MT, ZIP 59759
The last spring frost here typically falls around 06/13, about 289 days from today. The first fall frost typically arrives around 09/05, about 83 frost-free days later.
Zone 5a (-20 to -15°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 Whitehall, not a forecast for this year.
What to do before the first frost
Zone 5a around Whitehall has about 1 week 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.
How much risk comes with planting early here
06/13 is the middle of 30 years of NOAA records, not a promise. Plant by 05/27 and you're betting against frost in roughly 9 years out of 10. 07/01 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Whitehall compares
About 83 days separate Whitehall's last and first frost, putting it 40,020 of 40,283 ZIP codes nationally. Within MT, it ranks 356 of 392.
Learn more
local microclimates explains what one yard in Whitehall can differ from the 59759 normal, and zone vs. frost date explains why Zone 5a and Whitehall's frost date answer different questions.