Morrison, CO 80465 Frost Dates
Frost dates for Morrison, CO, ZIP 80465
Typically, the last spring freeze lands around 05/02, roughly 247 days out. The first fall frost typically arrives around 10/11, about 160 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 Morrison, not a forecast for this year.
What to do before the first frost
Zone 5b around Morrison has about 6 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 Morrison's last frost
05/02 is the middle of 30 years of NOAA records, not a promise. Plant by 04/20 and you're betting against frost in roughly 9 years out of 10. 05/17 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Morrison compares
About 160 days separate Morrison's last and first frost, putting it 32,502 of 40,283 ZIP codes nationally. Within CO, it ranks 107 of 624.
Learn more
the frost range explains how to read the range around Morrison's dates instead of trusting one, and local microclimates explains what one yard in Morrison can differ from the 80465 normal.