Aspen, CO 81611 Frost Dates
Frost dates for Aspen, CO, ZIP 81611
Around 06/02 is the usual last spring frost, about 278 days away. The first fall frost typically arrives around 09/23, about 113 frost-free days later.
Aspen sits in USDA Zone 5a (-20 to -15°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.
What to do before the first frost
Zone 5a around Aspen has about 4 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.
The actual range around Aspen's last frost
06/02 is the middle of 30 years of NOAA records, not a promise. Plant by 05/17 and you're betting against frost in roughly 9 years out of 10. 06/17 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Aspen compares
At roughly 113 frost-free days, Aspen places 39,387 of 40,283 ZIP codes in this dataset. Within CO, it ranks 494 of 624.
Learn more
local microclimates explains what one yard in Aspen can differ from the 81611 normal, and zone vs. frost date explains why Zone 5a and Aspen's frost date answer different questions.