Riggins, ID 83542 Frost Dates
Frost dates for Riggins, ID, ZIP 83542
Typically, the last spring freeze lands around 05/06, roughly 251 days out. The first fall frost typically arrives around 10/09, about 155 frost-free days later.
The USDA Plant Hardiness Zone Map puts Riggins in Zone 7a (0 to 5°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 7a around Riggins has about 6 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.
The actual range around Riggins's last frost
05/06 is the middle of 30 years of NOAA records, not a promise. Plant by 04/23 and you're betting against frost in roughly 9 years out of 10. 05/26 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Riggins compares
At roughly 155 frost-free days, Riggins places 34,107 of 40,283 ZIP codes in this dataset. Within ID, it ranks 94 of 320.
Learn more
zone vs. frost date explains why Zone 7a and Riggins's frost date answer different questions, and the frost range explains how to read the range around Riggins's dates instead of trusting one.