Denver, CO 80010 Frost Dates
80010, near Denver, CO: the frost window
Typically, the last spring freeze lands around 05/04, roughly 249 days out. Fall's first freeze usually shows up around 10/08, roughly 156 days after the last spring frost.
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.
Stretching the season past the first frost
Denver's growing season runs out in roughly 6 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 05/04 isn't a guarantee
05/04 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/20 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/16 and only about 1 year in 10 sees frost after that.
Denver against the rest of the dataset
Denver's growing season runs about 156 days, ranking 33,474 of 40,283 US ZIP codes measured here, longest to shortest. Within CO, it ranks 182 of 624.
Learn more
Two guides worth reading on 80010: zone vs. frost date, on why Zone 6a and Denver's frost date answer different questions, and the frost range, on how to read the range around Denver's dates instead of trusting one.