South Tucson, AZ 85705 Frost Dates
Frost dates for South Tucson, AZ, ZIP 85705
Typically, the last spring freeze lands around 02/11, roughly 167 days out. The first fall frost typically arrives around 12/02, about 293 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 South Tucson, not a forecast for this year.
What to do before the first frost
Zone 9b around South Tucson 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 02/11 isn't a guarantee
02/11 is the middle of 30 years of NOAA records, not a promise. Plant by 01/16 and you're betting against frost in roughly 9 years out of 10. 03/07 is the safer bet, historically only a 1-in-10 chance of frost that late.
How South Tucson compares
At roughly 293 frost-free days, South Tucson places 4,294 of 40,283 ZIP codes in this dataset. Within AZ, it ranks 276 of 506.
Learn more
zone vs. frost date explains why Zone 9b and South Tucson's frost date answer different questions, and the frost range explains how to read the range around South Tucson's dates instead of trusting one.