Jamestown, CO 80308 Frost Dates
Jamestown, CO: when does the frost end?
Typically, the last spring freeze lands around 05/24, roughly 269 days out. Fall's first freeze usually shows up around 09/23, roughly 120 days after the last spring frost.
Jamestown 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 4 weeks until Jamestown'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
05/24 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/11 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/10 and only about 1 year in 10 sees frost after that.
Jamestown against the rest of the dataset
At roughly 120 frost-free days, Jamestown places 39,105 of 40,283 ZIP codes in this dataset. Within CO, it ranks 463 of 624.
Learn more
Before leaning on 80308's figures: zone vs. frost date explains why Zone 6a and Jamestown's frost date answer different questions, while the frost range explains how to read the range around Jamestown's dates instead of trusting one.