Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for Phoenix, AZ

Phoenix, AZ is in USDA zones 9b to 10a across its 74 ZIP codes.

Phoenix on the zone map

Outlined: its 43 ZIP code areas · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zones9b–10a25 to 35 °F

ZIP codes74

Last frostrare

First frostrare

Growing seasonall year

9b 32 ZIPs 10a 42 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Phoenix, AZ…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates

A 32 °F frost doesn't happen here in most winters. At the nearest station (NOAA station Phoenix Sky Harbor Intl Airport, AZ, elevation 1,106 ft) the median growing season is 365 days. When frost does come, it is a midwinter night or two; cover tender plants when a freeze is forecast.

Frost data: NOAA NCEI U.S. Climate Normals 1991–2020.

When spring arrived in 2026

In 2026, spring leaf-out near 85012 came on Jan 19 — 4 days earlier than the 1991–2020 average (Jan 23).

average
Jan 232026
Jan 19

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Soil in Phoenix, AZ

The soil mapped at the center of ZIP 85012 is Mohall — clay loam, well drained.

TextureClay loamholds water and nutrients; slow to drain and warm up

pH8.2alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter0.75%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Mohall clay loam.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 85012; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Phoenix, AZ

Summer high107 °Faverage high, July

Winter low45 °Faverage low, December

Hot days173days a year at 90 °F or more

Freezing nights1nights a year at 32 °F or less

Growing degree days9,390base 50 °F — the season’s usable heat

Longest day14 h 22 mindaylight on June 21

Shortest day9 h 56 mindaylight on December 21

Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully

Precipitation8.7 inper year, rain and melted snow

Average high and low, by month

Precipitation by month inches

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Phoenix Sky Harbor Intl Airport, AZ (7 mi away); precipitation: Phoenix 3.8 Nnw, AZ (within 1 mile). Daylight is calculated from latitude.