Morrison, CO 80425 Frost Dates
Frost dates for Morrison, CO, ZIP 80425
The last spring frost here typically falls around 05/16, about 261 days from today. The first fall frost typically arrives around 09/29, about 132 frost-free days later.
Morrison sits in USDA Zone 5b (-15 to -10°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 5b around Morrison has about 5 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.
How much risk comes with planting early here
05/16 is the middle of 30 years of NOAA records, not a promise. Plant by 05/03 and you're betting against frost in roughly 9 years out of 10. 06/06 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Morrison compares
At roughly 132 frost-free days, Morrison places 38,217 of 40,283 ZIP codes in this dataset. Within CO, it ranks 436 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 80425 normal.