Ammon, ID 83406 Frost Dates
When can you plant in Ammon, ID?
Typically, the last spring freeze lands around 05/09, roughly 254 days out. The first fall frost typically arrives around 10/01, about 142 frost-free days later.
The USDA Plant Hardiness Zone Map puts Ammon in Zone 5b (-15 to -10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
About 5 weeks of growing season left in Ammon 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 04/27 and you're betting against frost in roughly 9 years out of 10. 06/02 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Ammon compares
About 142 days separate Ammon's last and first frost, putting it 36,711 of 40,283 ZIP codes nationally. Within ID, it ranks 143 of 320.
Learn more
local microclimates covers what one yard in Ammon can differ from the 83406 normal. zone vs. frost date covers why Zone 5b and Ammon's frost date answer different questions.