Brighton, CO 80601 Frost Dates
Frost dates for Brighton, CO, ZIP 80601
Typically, the last spring freeze lands around 05/03, roughly 248 days out. The first fall frost typically arrives around 10/07, about 155 frost-free days later.
The USDA Plant Hardiness Zone Map puts Brighton 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 Brighton 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 Brighton compares
Brighton's growing season runs about 155 days, ranking 33,917 of 40,283 US ZIP codes measured here, longest to shortest. Within CO, it ranks 242 of 624.
Learn more
the frost range explains how to read the range around Brighton's dates instead of trusting one, and local microclimates explains what one yard in Brighton can differ from the 80601 normal.