Growli

USDA hardiness zones — 2023 map

Arizona hardiness zones — USDA planting zone map + what to grow

Zones 4b-10b · most of Arizona is zone 9a · Southwest region

ArizonaUSDA zone range & map

On the 2023 USDA Plant Hardiness Zone Map, Arizona spans zones 4b-10b. The map shades the state from the high country around Flagstaff (zone 4b-6a) through to the low desert around Yuma and Phoenix (zone 10b). The single most common half-zone across the populated state is zone 9a — that is the figure to use if you only remember one number for Arizona. Arizona ranges from snowy mountain forest to frost-free low desert. In the desert, summer heat is the binding constraint and winter is the prime growing season.

USDA zone rangeZones 4b-10b
Most common zoneZone 9a
Coldest areathe high country around Flagstaff (zone 4b-6a)
Warmest areathe low desert around Yuma and Phoenix (zone 10b)
Average last spring frostmid-February (low desert)
Average first fall frostearly December (low desert)

Source: USDA 2023 Plant Hardiness Zone Map (1991-2020 normals). Frost averages: NOAA/NCEI 1991-2020 climate normals. Local ZIP-level zones and frost dates can differ from these statewide figures.

Arizona hardiness zones by major city

Zones shift across Arizona with elevation and distance from the coast. Here is the 2023 USDA half-zone for the largest cities:

CityUSDA zone
PhoenixZone 10a
TucsonZone 9b
FlagstaffZone 6a
YumaZone 10b
MesaZone 10a

Need your exact zone? Run the ZIP-code zone finder for a precise half-zone and frost dates for your address.

ZIP-code zones in Arizona

Statewide ranges hide a lot. Tap your area for its exact USDA half-zone, last and first frost dates, and what to plant now:

What Arizona's zone range means for planting

Your hardiness zone tells you which perennials, shrubs, and trees will survive a typical Arizona winter, and it anchors when tender crops can go outside. Because Arizona spans 4b-10b, two gardeners in the same state can have very different planting calendars.

Find your exact zone in Arizona

The 4b-10b range is statewide. Growli pins your hardiness zone and frost dates to your exact ZIP code and sends a push notification before any forecast frost night for your saved location.

Frequently asked questions

What hardiness zone is Arizona?

Arizona spans USDA hardiness zones 4b-10b on the 2023 USDA Plant Hardiness Zone Map. The most common zone — covering the largest share of the populated state — is zone 9a. The coldest areas are the high country around Flagstaff (zone 4b-6a) and the warmest are the low desert around Yuma and Phoenix (zone 10b).

When is the last frost in Arizona?

Across most of Arizona the average last spring frost falls around mid-February (low desert) and the first fall frost around early December (low desert). These are statewide averages — colder, higher areas run later in spring and earlier in fall, so check a ZIP-level estimate for your exact spot.

What grows well in Arizona?

Arizona ranges from snowy mountain forest to frost-free low desert. In the desert, summer heat is the binding constraint and winter is the prime growing season. Match plants to your local half-zone within the 4b-10b range: choose varieties hardy to at least zone 9a for reliable overwintering, and time tender crops around your local frost dates. The zone 9 planting guide lists vegetables, fruit, and ornamentals suited to most of the state.

Why does Arizona have more than one hardiness zone?

Hardiness zones track the average annual coldest temperature, which changes with latitude, elevation, distance from water, and urban heat. That is why Arizona ranges from the high country around Flagstaff (zone 4b-6a) to the low desert around Yuma and Phoenix (zone 10b) — a span of 4b-10b — even though it is a single state.

Did Arizona's hardiness zone change in 2023?

The USDA updated the Plant Hardiness Zone Map in November 2023 using 1991-2020 climate data. About half the country, including parts of Arizona, shifted to the next warmer half-zone versus the 2012 map. The 4b-10b range here reflects the current 2023 map. Always confirm your address against the official USDA map for plant-survival decisions.

Related guides