Grangeville, ID 83530 Frost Dates
When can you plant in Grangeville, ID?
The last spring frost here typically falls around 05/09, about 254 days from today. The first fall frost typically arrives around 10/03, about 146 frost-free days later.
Grangeville sits in USDA Zone 6b (-5 to 0°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
About 5 weeks of growing season left in Grangeville before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 05/09 isn't a guarantee
05/09 is the middle of 30 years of NOAA records, not a promise. Plant by 04/24 and you're betting against frost in roughly 9 years out of 10. 05/27 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Grangeville compares
About 146 days separate Grangeville's last and first frost, putting it 36,048 of 40,283 ZIP codes nationally. Within ID, it ranks 135 of 320.
Learn more
local microclimates covers what one yard in Grangeville can differ from the 83530 normal. zone vs. frost date covers why Zone 6b and Grangeville's frost date answer different questions.