Oro Valley, AZ 85739 Frost Dates
Oro Valley, AZ: when does the frost end?
Around 03/23 is the usual last spring frost, about 207 days away. Fall's first freeze usually shows up around 11/22, roughly 242 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Oro Valley in Zone 9a (20 to 25°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
With roughly 12 weeks until Oro Valley's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 03/23 isn't a guarantee
03/23 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 02/18 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/16 and only about 1 year in 10 sees frost after that.
Oro Valley against the rest of the dataset
At roughly 242 frost-free days, Oro Valley places 8,344 of 40,283 ZIP codes in this dataset. Within AZ, it ranks 325 of 506.
Learn more
Before leaning on 85739's figures: the frost range explains how to read the range around Oro Valley's dates instead of trusting one, while local microclimates explains what one yard in Oro Valley can differ from the 85739 normal.