Antonito, CO 81120 Frost Dates
Frost dates for Antonito, CO, ZIP 81120
Typically, the last spring freeze lands around 05/28, roughly 273 days out. The first fall frost typically arrives around 09/21, about 115 frost-free days later.
Zone 5b (-15 to -10°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Antonito, not a forecast for this year.
What to do before the first frost
Zone 5b around Antonito has about 3 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 Antonito's last frost
05/28 is the middle of 30 years of NOAA records, not a promise. Plant by 05/13 and you're betting against frost in roughly 9 years out of 10. 06/11 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Antonito compares
At roughly 115 frost-free days, Antonito places 39,332 of 40,283 ZIP codes in this dataset. Within CO, it ranks 486 of 624.
Learn more
the frost range explains how to read the range around Antonito's dates instead of trusting one, and local microclimates explains what one yard in Antonito can differ from the 81120 normal.