Afton, WY 83126 Frost Dates
Frost dates for Afton, WY, ZIP 83126
Typically, the last spring freeze lands around 06/20, roughly 296 days out. The first fall frost typically arrives around 09/01, about 71 frost-free days later.
Afton sits in USDA Zone 5a (-20 to -15°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
Zone 5a around Afton has about 1 week 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 06/20 isn't a guarantee
06/20 is the middle of 30 years of NOAA records, not a promise. Plant by 06/02 and you're betting against frost in roughly 9 years out of 10. 07/07 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Afton compares
About 71 days separate Afton's last and first frost, putting it 40,112 of 40,283 ZIP codes nationally. Within WY, it ranks 167 of 192.
Learn more
zone vs. frost date explains why Zone 5a and Afton's frost date answer different questions, and the frost range explains how to read the range around Afton's dates instead of trusting one.