Sierra Vista, AZ 85650 Frost Dates
85650, near Sierra Vista, AZ: the frost window
Typically, the last spring freeze lands around 04/05, roughly 220 days out. Fall's first freeze usually shows up around 11/09, roughly 216 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Sierra Vista in Zone 8b (15 to 20°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
Sierra Vista's growing season runs out in roughly 10 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/05 isn't a guarantee
04/05 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/15 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/21 and only about 1 year in 10 sees frost after that.
Sierra Vista against the rest of the dataset
At roughly 216 frost-free days, Sierra Vista places 13,720 of 40,283 ZIP codes in this dataset. Within AZ, it ranks 369 of 506.
Learn more
Two guides worth reading on 85650: zone vs. frost date, on why Zone 8b and Sierra Vista's frost date answer different questions, and the frost range, on how to read the range around Sierra Vista's dates instead of trusting one.