Tucson, AZ 85641 Frost Dates
85641, near Tucson, AZ: the frost window
Around 01/26 is the usual last spring frost, about 151 days away. Fall's first freeze usually shows up around 12/16, roughly 326 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 Tucson, not a forecast for this year.
Stretching the season past the first frost
Tucson's growing season runs out in roughly 16 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
01/26 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 02/25 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 12/24 and only about 1 year in 10 sees frost after that.
Tucson against the rest of the dataset
Tucson's growing season runs about 326 days, ranking 3,202 of 40,283 US ZIP codes measured here, longest to shortest. Within AZ, it ranks 190 of 506.
Learn more
Two guides worth reading on 85641: local microclimates, on what one yard in Tucson can differ from the 85641 normal, and zone vs. frost date, on why Zone 9a and Tucson's frost date answer different questions.