Challis, ID 83235 Frost Dates
Frost dates for Challis, ID, ZIP 83235
The last spring frost here typically falls around 05/14, about 259 days from today. The first fall frost typically arrives around 09/25, about 131 frost-free days later.
The USDA Plant Hardiness Zone Map puts Challis 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
Zone 5b around Challis has about 4 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.
How much risk comes with planting early here
05/14 is the middle of 30 years of NOAA records, not a promise. Plant by 05/02 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 Challis compares
Challis's growing season runs about 131 days, ranking 38,308 of 40,283 US ZIP codes measured here, longest to shortest. Within ID, it ranks 176 of 320.
Learn more
local microclimates explains what one yard in Challis can differ from the 83235 normal, and zone vs. frost date explains why Zone 5b and Challis's frost date answer different questions.