Frederick, CO 80520 Frost Dates
Frost dates for Frederick, CO, ZIP 80520
Around 05/03 is the usual last spring frost, about 248 days away. The first fall frost typically arrives around 10/07, about 155 frost-free days later.
The USDA Plant Hardiness Zone Map puts Frederick in Zone 5b (-15 to -10°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 5b around Frederick 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 05/03 isn't a guarantee
05/03 is the middle of 30 years of NOAA records, not a promise. Plant by 04/22 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 Frederick compares
About 155 days separate Frederick's last and first frost, putting it 33,927 of 40,283 ZIP codes nationally. Within CO, it ranks 245 of 624.
Learn more
local microclimates explains what one yard in Frederick can differ from the 80520 normal, and zone vs. frost date explains why Zone 5b and Frederick's frost date answer different questions.