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

Planting zone for 85288 — Tempe, AZ

ZIP code 85288 (Tempe, Maricopa County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is February 13 and the first fall frost December 5.

Where ZIP 85288 is

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.

Zone9b25 to 30 °F

Coldest night−3.9 to −1.1 °C

Last frostFeb 13

First frostDec 5

2012 zone—

The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 9b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Tempe, 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 in Tempe, AZ

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostFebruary 13median — 50% chance of a later frost

Safe for tender plantsMarch 9only 10% chance of frost after

First fall frostDecember 5median — 10% chance by Nov 18

Growing season298 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 16 and returns around December 19.

From the NOAA station Tempe Asu, AZ — within 1 mile, elevation 1,168 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 85288

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Jan 2 – Jan 16

SpinachSow outdoors · Jan 2 – Jan 23

Broccoli, cabbageStart indoors · Dec 5 – Dec 19

Broccoli, cabbageTransplant · Jan 23 – Feb 6

Onion setsPlant outdoors · Jan 16 – Jan 30

PotatoesPlant outdoors · Jan 23 – Feb 6

LettuceSow outdoors · Jan 16 – Jan 30

Carrots, beetsSow outdoors · Jan 23 – Feb 6

TomatoesStart indoors · Dec 19 – Jan 2

TomatoesTransplant · Feb 20 – Mar 6

Peppers, eggplantStart indoors · Dec 5 – Dec 19

Peppers, eggplantTransplant · Feb 27 – Mar 13

BeansSow outdoors · Feb 20 – Mar 6

Sweet cornSow outdoors · Feb 20 – Mar 6

Cucumbers, squashSow outdoors · Feb 20 – Mar 6

Fall lettuce, spinachSow outdoors · Oct 10 – Oct 24

GarlicPlant cloves · Nov 21 – Dec 26

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 13) and first fall frost (Dec 5) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 85288 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).

Native plants for zone 9b in Arizona

499 plants native to the lower 48 states, recorded in Arizona, and rated by the USDA to survive 25 °F or colder — the bottom of zone 9b. Each links to its USDA PLANTS profile.

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Tempe, AZ.

Soil in Tempe, AZ

The soil mapped at the center of ZIP 85288 is Gilman — loam, well drained.

TextureLoama good balance for most vegetables

pH8.2alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter0.25%low — add compost

Hydrologic groupBwater soaks in moderately

Farmland classPrime farmland if irrigated and either protected from flooding or not frequently flooded during the growing seasonUSDA classification

Map unit: Gilman 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 85288; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Tempe, AZ

Summer high106 °Faverage high, July

Winter low38 °Faverage low, December

Hot days179days a year at 90 °F or more

Freezing nights10nights a year at 32 °F or less

Growing degree days8,036base 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

Precipitation8.8 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: Tempe Asu, AZ (within 1 mile); precipitation: Scottsdale 3.7 Ssw, AZ (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

4 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

852819b

Tempe, AZ · 1 mi

852579b

Scottsdale, AZ · 2 mi

Scottsdale, AZ · 4 mi

8500810a

Phoenix, AZ · 4 mi

All 7 ZIP codes in Tempe → · Arizona planting zones →

Questions about 85288

What planting zone is ZIP code 85288?

ZIP code 85288 (Tempe, AZ) is in USDA hardiness zone 9b on the 2023 map: the coldest night of an average winter reaches 25 to 30 °F (−3.9 to −1.1 °C).

When is the last frost in Tempe, AZ?

The median last spring frost (32 °F) near 85288 is February 13; after March 9 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Tempe Asu station.

When is the first frost in Tempe, AZ?

The median first fall frost near 85288 is December 5, giving a median frost-free growing season of 298 days.

When should I plant tomatoes in 85288?

Start tomato seeds indoors around Dec 19 – Jan 2 and set transplants outside around Feb 20 – Mar 6, one to three weeks after the median last frost.

How much rain and snow does 85288 get?

About 8.8 inches of precipitation a year (NOAA 1991–2020 normals, Scottsdale 3.7 Ssw station).

How hot do summers get in Tempe, AZ?

The average high peaks at 106 °F in July, with about 179 days a year at 90 °F or more.

What kind of soil does 85288 have?

The USDA soil survey maps Gilman at the center of ZIP 85288: loam, well drained, pH about 8.2 (alkaline).

Did spring come early in Tempe, AZ in 2026?

Spring leaf-out near 85288 came on Jan 19 in 2026, 4 days earlier than the 1991–2020 average (Jan 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Tempe, AZ?

Intermediate onions: the longest day near 85288 is 14 h 22 min, so day-neutral types bulb best; long-day varieties may not bulb fully.