Milliken, CO 80543 Frost Dates
80543, near Milliken, CO: the frost window
Around 05/02 is the usual last spring frost, about 247 days away. Fall's first freeze usually shows up around 10/08, roughly 159 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Milliken in Zone 5b (-15 to -10°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
Milliken'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 05/02 isn't a guarantee
05/02 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/17 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/14 and only about 1 year in 10 sees frost after that.
Milliken against the rest of the dataset
At roughly 159 frost-free days, Milliken places 32,628 of 40,283 ZIP codes in this dataset. Within CO, it ranks 111 of 624.
Learn more
Two guides worth reading on 80543: zone vs. frost date, on why Zone 5b and Milliken's frost date answer different questions, and the frost range, on how to read the range around Milliken's dates instead of trusting one.