Denver, CO 80011 Frost Dates
Frost dates for Denver, CO, ZIP 80011
Typically, the last spring freeze lands around 05/04, roughly 249 days out. The first fall frost typically arrives around 10/08, about 156 frost-free days later.
The USDA Plant Hardiness Zone Map puts Denver in Zone 6a (-10 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 6a around Denver 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.
Why 05/04 isn't a guarantee
05/04 is the middle of 30 years of NOAA records, not a promise. Plant by 04/20 and you're betting against frost in roughly 9 years out of 10. 05/16 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Denver compares
Denver's growing season runs about 156 days, ranking 33,475 of 40,283 US ZIP codes measured here, longest to shortest. Within CO, it ranks 183 of 624.
Learn more
local microclimates explains what one yard in Denver can differ from the 80011 normal, and zone vs. frost date explains why Zone 6a and Denver's frost date answer different questions.