Broomfield, CO 80020 Frost Dates
Broomfield, CO: when does the frost end?
Typically, the last spring freeze lands around 05/02, roughly 247 days out. Fall's first freeze usually shows up around 10/11, roughly 160 days after the last spring frost.
Broomfield 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
With roughly 6 weeks until Broomfield's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
How much risk comes with planting early here
05/02 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/18 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.
Broomfield against the rest of the dataset
About 160 days separate Broomfield's last and first frost, putting it 32,194 of 40,283 ZIP codes nationally. Within CO, it ranks 88 of 624.
Learn more
Before leaning on 80020's figures: zone vs. frost date explains why Zone 6a and Broomfield's frost date answer different questions, while the frost range explains how to read the range around Broomfield's dates instead of trusting one.