Morrison, CO 80006 Frost Dates
80006, near Morrison, CO: the frost window
Typically, the last spring freeze lands around 05/08, roughly 253 days out. Fall's first freeze usually shows up around 10/03, roughly 147 days after the last spring frost.
Morrison sits in USDA Zone 6a (-10 to -5°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
Stretching the season past the first frost
Morrison'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.
Why 05/08 isn't a guarantee
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.
Morrison against the rest of the dataset
At roughly 147 frost-free days, Morrison places 35,965 of 40,283 ZIP codes in this dataset. Within CO, it ranks 352 of 624.
Learn more
Two guides worth reading on 80006: zone vs. frost date, on why Zone 6a and Morrison's frost date answer different questions, and the frost range, on how to read the range around Morrison's dates instead of trusting one.