Maricopa, AZ 85138 Frost Dates
Frost dates for Maricopa, AZ, ZIP 85138
Typically, the last spring freeze lands around 02/23, roughly 179 days out. The first fall frost typically arrives around 11/24, about 274 frost-free days later.
The USDA Plant Hardiness Zone Map puts Maricopa in Zone 9a (20 to 25°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 9a around Maricopa has about 13 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
02/23 is the middle of 30 years of NOAA records, not a promise. Plant by 01/29 and you're betting against frost in roughly 9 years out of 10. 03/15 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Maricopa compares
About 274 days separate Maricopa's last and first frost, putting it 5,142 of 40,283 ZIP codes nationally. Within AZ, it ranks 304 of 506.
Learn more
zone vs. frost date explains why Zone 9a and Maricopa's frost date answer different questions, and the frost range explains how to read the range around Maricopa's dates instead of trusting one.