Casa Grande, AZ 85121 Frost Dates
Frost dates for Casa Grande, AZ, ZIP 85121
Around 02/05 is the usual last spring frost, about 161 days away. The first fall frost typically arrives around 12/06, about 305 frost-free days later.
Zone 9b (25 to 30°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.
What to do before the first frost
Zone 9b around Casa Grande has about 14 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 02/05 isn't a guarantee
02/05 is the middle of 30 years of NOAA records, not a promise. Plant by 01/05 and you're betting against frost in roughly 9 years out of 10. 02/28 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Casa Grande compares
About 305 days separate Casa Grande's last and first frost, putting it 3,728 of 40,283 ZIP codes nationally. Within AZ, it ranks 245 of 506.
Learn more
the frost range explains how to read the range around Casa Grande's dates instead of trusting one, and local microclimates explains what one yard in Casa Grande can differ from the 85121 normal.