Casa Grande, AZ 85122 Frost Dates
85122, near Casa Grande, AZ: the frost window
Typically, the last spring freeze lands around 02/05, roughly 161 days out. Fall's first freeze usually shows up around 12/06, roughly 305 days after the last spring frost.
Zone 9a (20 to 25°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 Casa Grande, not a forecast for this year.
Stretching the season past the first frost
Casa Grande's growing season runs out in roughly 14 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 02/05 isn't a guarantee
02/05 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 01/05 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 02/28 and only about 1 year in 10 sees frost after that.
Casa Grande against the rest of the dataset
At roughly 305 frost-free days, Casa Grande places 3,729 of 40,283 ZIP codes in this dataset. Within AZ, it ranks 246 of 506.
Learn more
Two guides worth reading on 85122: zone vs. frost date, on why Zone 9a and Casa Grande's frost date answer different questions, and the frost range, on how to read the range around Casa Grande's dates instead of trusting one.