Jamestown, CO 80510 Frost Dates
Frost dates for Jamestown, CO, ZIP 80510
The last spring frost here typically falls around 06/14, about 290 days from today. The first fall frost typically arrives around 09/12, about 92 frost-free days later.
The USDA Plant Hardiness Zone Map puts Jamestown in Zone 5b (-15 to -10°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 5b around Jamestown has about 2 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
Why 06/14 isn't a guarantee
06/14 is the middle of 30 years of NOAA records, not a promise. Plant by 05/24 and you're betting against frost in roughly 9 years out of 10. 06/28 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Jamestown compares
Jamestown's growing season runs about 92 days, ranking 39,893 of 40,283 US ZIP codes measured here, longest to shortest. Within CO, it ranks 545 of 624.
Learn more
local microclimates explains what one yard in Jamestown can differ from the 80510 normal, and zone vs. frost date explains why Zone 5b and Jamestown's frost date answer different questions.