Planting zones · Phoenix, Arizona
What Planting Zone Is Phoenix?
Phoenix is in USDA zone 9b–10a. Low Sonoran Desert valley at about 1,100 ft: about 7.2 in. of precipitation split between winter storms and the summer monsoon, and average July highs above 106°F. At Sky Harbor a 32°F freeze occurs in fewer than one year in five, but outlying stations such as Scottsdale and Chandler Heights freeze far more often.
- USDA zone (2023)9b–10a
- Coldest night (avg.)30 to 35°FZIP 85004
- Annual precipitation7.2 inches
Phoenix hardiness zone by ZIP code
On the 2023 USDA Plant Hardiness Zone Map, the ZIP codes we sampled in Phoenix fall in zones 9b to 10a; 85004 (zone 10a) has an average annual extreme minimum of 30 to 35°F. Choose perennials, shrubs, and trees rated at least to zone 9.
| ZIP | Zone | Avg. coldest night |
|---|---|---|
| 85004 | 10a | 30 to 35°F |
| 85016 | 10a | 30 to 35°F |
| 85032 | 9b | 25 to 30°F |
| 85224 | 9b | 25 to 30°F |
| 85254 | 10a | 30 to 35°F |
| 85301 | 9b | 25 to 30°F |
Not listed? Look up any ZIP code.
Frost dates and when to plant
A 32°F freeze occurs in only about 18% of years at Phoenix Sky Harbor Intl Airport, so median frost dates aren't meaningful. Frost-tender plants still need protection on the rare cold night.
In the low desert, fall is the preferred planting season: roots grow through the mild winter before the first summer heat. Avoid planting in midsummer.
Rainfall and heat in Phoenix
Average annual precipitation is 7.2 inches (Phoenix Sky Harbor Intl Airport, 1991–2020), spread across the year with August the wettest month and June the driest.
The average high in July is about 107°F and the average low in December is about 45°F, measured at about 1,110 ft.
That is why a zone rating alone isn't enough for a xeriscape here: pick plants that are both cold-hardy to zone 9 and rated very low or low water once established.
Low-water plants for Phoenix
52 plants in our database are hardy to zone 9 and suited to zone 9. Here are 12, driest first, across plant types.
'Desert Museum' Palo VerdeParkinsonia 'Desert Museum'Zones 8–11 · Very low water
Adam's Needle YuccaYucca filamentosaZones 4–10 · Very low water
Big SagebrushArtemisia tridentataZones 4–9 · Very low water
Blue GramaBouteloua gracilisZones 3–10 · Very low water
California FuchsiaEpilobium canum (syn. Zauschneria californica)Zones 8–10 · Very low water
Claret Cup CactusEchinocereus triglochidiatusZones 5–9 · Very low water
Hardy Ice PlantDelosperma cooperiZones 5–9 · Very low water
Blue Palo VerdeParkinsonia floridaZones 8–11 · Very low water
Havard AgaveAgave havardianaZones 5–9 · Very low water
Blueblossom CeanothusCeanothus thyrsiflorusZones 8–10 · Very low water
Little BluestemSchizachyrium scopariumZones 3–9 · Very low water
Chocolate FlowerBerlandiera lyrataZones 4–9 · Very low water
Frequently asked questions
What planting zone is Phoenix?
Phoenix, AZ is in USDA hardiness zone 9b–10a on the 2023 USDA Plant Hardiness Zone Map, based on the ZIP codes we sampled (85004: 10a, 85016: 10a, 85032: 9b, 85224: 9b, 85254: 10a, 85301: 9b). In 85004, the average coldest night of the year is 30 to 35°F.
When is the last frost in Phoenix?
A 32°F freeze occurs in only about 18% of years at Phoenix Sky Harbor Intl Airport, so median frost dates aren't meaningful. Frost-tender plants still need protection on the rare cold night.
How much rain does Phoenix get?
Average annual precipitation is 7.2 inches (Phoenix Sky Harbor Intl Airport, 1991–2020), spread across the year with August the wettest month and June the driest.
Sources
- NOAA NCEI U.S. Climate Normals 1991–2020, Phoenix Sky Harbor Intl Airport (USW00023183). ncei.noaa.gov
- USDA ARS 2023 Plant Hardiness Zone Map, by ZIP. planthardiness.ars.usda.gov