Tombstone, AZ 85671 Frost Dates
85671, near Tombstone, AZ: the frost window
Typically, the last spring freeze lands around 04/14, roughly 229 days out. Fall's first freeze usually shows up around 11/02, roughly 200 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Tombstone 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
Tombstone's growing season runs out in roughly 9 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
04/14 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/28 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/30 and only about 1 year in 10 sees frost after that.
Tombstone against the rest of the dataset
Tombstone's growing season runs about 200 days, ranking 17,834 of 40,283 US ZIP codes measured here, longest to shortest. Within AZ, it ranks 389 of 506.
Learn more
Two guides worth reading on 85671: local microclimates, on what one yard in Tombstone can differ from the 85671 normal, and zone vs. frost date, on why Zone 8b and Tombstone's frost date answer different questions.