Aurora, CO 80249 Frost Dates
80249, near Aurora, CO: the frost window
The last spring frost here typically falls around 05/05, about 250 days from today. Fall's first freeze usually shows up around 10/09, roughly 156 days after the last spring frost.
Zone 6a (-10 to -5°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 Aurora, not a forecast for this year.
Stretching the season past the first frost
Aurora'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 05/05 isn't a guarantee
05/05 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/23 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/19 and only about 1 year in 10 sees frost after that.
Aurora against the rest of the dataset
About 156 days separate Aurora's last and first frost, putting it 33,484 of 40,283 ZIP codes nationally. Within CO, it ranks 192 of 624.
Learn more
Two guides worth reading on 80249: local microclimates, on what one yard in Aurora can differ from the 80249 normal, and zone vs. frost date, on why Zone 6a and Aurora's frost date answer different questions.