Dayton, WY 82838 Frost Dates
Frost dates for Dayton, WY, ZIP 82838
Typically, the last spring freeze lands around 05/24, roughly 269 days out. The first fall frost typically arrives around 09/18, about 114 frost-free days later.
The USDA Plant Hardiness Zone Map puts Dayton in Zone 5a (-20 to -15°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 5a around Dayton has about 3 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
05/24 is the middle of 30 years of NOAA records, not a promise. Plant by 05/11 and you're betting against frost in roughly 9 years out of 10. 06/07 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Dayton compares
Dayton's growing season runs about 114 days, ranking 39,363 of 40,283 US ZIP codes measured here, longest to shortest. Within WY, it ranks 124 of 192.
Learn more
zone vs. frost date explains why Zone 5a and Dayton's frost date answer different questions, and the frost range explains how to read the range around Dayton's dates instead of trusting one.