Jamestown, CO 80038 Frost Dates
80038, near Jamestown, CO: the frost window
Typically, the last spring freeze lands around 05/06, roughly 251 days out. Fall's first freeze usually shows up around 10/05, roughly 151 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
Jamestown'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
05/06 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/24 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/18 and only about 1 year in 10 sees frost after that.
Jamestown against the rest of the dataset
At roughly 151 frost-free days, Jamestown places 35,169 of 40,283 ZIP codes in this dataset. Within CO, it ranks 316 of 624.
Learn more
Two guides worth reading on 80038: local microclimates, on what one yard in Jamestown can differ from the 80038 normal, and zone vs. frost date, on why Zone 6a and Jamestown's frost date answer different questions.