Flagstaff, AZ 86016 Frost Dates
Frost dates for Flagstaff, AZ, ZIP 86016
The last spring frost here typically falls around 04/07, about 222 days from today. The first fall frost typically arrives around 11/03, about 206 frost-free days later.
Zone 6b (-5 to 0°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 Flagstaff, not a forecast for this year.
What to do before the first frost
Zone 6b around Flagstaff has about 10 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 04/07 isn't a guarantee
04/07 is the middle of 30 years of NOAA records, not a promise. Plant by 03/17 and you're betting against frost in roughly 9 years out of 10. 04/30 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Flagstaff compares
At roughly 206 frost-free days, Flagstaff places 15,927 of 40,283 ZIP codes in this dataset. Within AZ, it ranks 375 of 506.
Learn more
the frost range explains how to read the range around Flagstaff's dates instead of trusting one, and local microclimates explains what one yard in Flagstaff can differ from the 86016 normal.