Challis, ID 83253 Frost Dates
Frost dates for Challis, ID, ZIP 83253
Around 05/14 is the usual last spring frost, about 259 days away. The first fall frost typically arrives around 09/25, about 131 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 Challis, not a forecast for this year.
What to do before the first frost
Zone 5a 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.
Why 05/14 isn't a guarantee
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
About 131 days separate Challis's last and first frost, putting it 38,309 of 40,283 ZIP codes nationally. Within ID, it ranks 177 of 320.
Learn more
zone vs. frost date explains why Zone 5a and Challis's frost date answer different questions, and the frost range explains how to read the range around Challis's dates instead of trusting one.