Littleton, CO 80129 Frost Dates
80129, near Littleton, CO: the frost window
The last spring frost here typically falls around 05/08, about 253 days from today. Fall's first freeze usually shows up around 10/03, roughly 147 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 Littleton, not a forecast for this year.
Stretching the season past the first frost
Littleton's growing season runs out in roughly 5 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
05/08 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/27 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/22 and only about 1 year in 10 sees frost after that.
Littleton against the rest of the dataset
Littleton's growing season runs about 147 days, ranking 35,839 of 40,283 US ZIP codes measured here, longest to shortest. Within CO, it ranks 343 of 624.
Learn more
Two guides worth reading on 80129: local microclimates, on what one yard in Littleton can differ from the 80129 normal, and zone vs. frost date, on why Zone 6a and Littleton's frost date answer different questions.