Firestone, CO 80504 Frost Dates
Frost dates for Firestone, CO, ZIP 80504
The last spring frost here typically falls around 05/06, about 251 days from today. The first fall frost typically arrives around 10/05, about 151 frost-free days later.
Zone 5b (-15 to -10°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Firestone, not a forecast for this year.
What to do before the first frost
Zone 5b around Firestone has about 5 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 Firestone's last frost
05/06 is the middle of 30 years of NOAA records, not a promise. Plant by 04/24 and you're betting against frost in roughly 9 years out of 10. 05/18 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Firestone compares
Firestone's growing season runs about 151 days, ranking 34,955 of 40,283 US ZIP codes measured here, longest to shortest. Within CO, it ranks 312 of 624.
Learn more
local microclimates explains what one yard in Firestone can differ from the 80504 normal, and zone vs. frost date explains why Zone 5b and Firestone's frost date answer different questions.