Mesa, AZ 85203 Frost Dates
85203, near Mesa, AZ: the frost window
Around 02/13 is the usual last spring frost, about 169 days away. Fall's first freeze usually shows up around 12/05, roughly 298 days after the last spring frost.
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 Mesa, not a forecast for this year.
Stretching the season past the first frost
Mesa'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.
How much risk comes with planting early here
02/13 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 01/12 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 03/09 and only about 1 year in 10 sees frost after that.
Mesa against the rest of the dataset
About 298 days separate Mesa's last and first frost, putting it 4,184 of 40,283 ZIP codes nationally. Within AZ, it ranks 255 of 506.
Learn more
Two guides worth reading on 85203: zone vs. frost date, on why Zone 9b and Mesa's frost date answer different questions, and the frost range, on how to read the range around Mesa's dates instead of trusting one.