Denver, CO 80239 Frost Dates
Frost dates for Denver, CO, ZIP 80239
The last spring frost here typically falls around 05/04, about 249 days from today. The first fall frost typically arrives around 10/08, about 156 frost-free days later.
Denver sits in USDA Zone 6a (-10 to -5°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 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.
The actual range around Denver's last frost
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 33,481 of 40,283 US ZIP codes measured here, longest to shortest. Within CO, it ranks 189 of 624.
Learn more
local microclimates explains what one yard in Denver can differ from the 80239 normal, and zone vs. frost date explains why Zone 6a and Denver's frost date answer different questions.