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

Planting zone for 85285 — Tempe, AZ

ZIP code 85285 (Tempe, Maricopa County) is in USDA zone 10a: the coldest winter night averages 30 to 35 °F. The median last spring frost is February 13 and the first fall frost December 5.

Where ZIP 85285 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.

Zone10a30 to 35 °F
Coldest night−1.1 to 1.7 °C
Last frostFeb 13
First frostDec 5
2012 zone9b

Was 9b on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 10a 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 85285

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 85285 came on Jan 19 — 4 days earlier than the 1991–2020 average (Jan 23).

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 10a in Arizona

506 plants native to the lower 48 states, recorded in Arizona, and rated by the USDA to survive 30 °F or colder — the bottom of zone 10a. Each links to its USDA PLANTS profile.

Trees 27

Arizona cypress50 ft · blooms spring · low shade tolerance · to −23 °FArizona madrone30 ft · blooms late spring · high shade tolerance · to −4 °FArizona sycamore80 ft · blooms early spring · high shade tolerance · to −8 °FArizona walnut50 ft · blooms late spring · high shade tolerance · to −33 °Fblack locust60 ft · blooms spring · high shade tolerance · to −37 °Fblue spruce100 ft · blooms late spring · medium shade tolerance · to −38 °F

Shrubs 118

alderleaf mountain mahogany15 ft · blooms late spring · medium shade tolerance · to −41 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °FAmerican tarwort3 ft · blooms late spring · high shade tolerance · to −23 °Fantelope bitterbrush6 ft · blooms early spring · medium shade tolerance · to −36 °FApache plume6 ft · blooms late spring · high shade tolerance · to −23 °Fbig sagebrush4 ft · blooms mid summer · high shade tolerance · to −43 °F

Wildflowers & perennials 199

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °Falpine mountainsorrel1 ft · blooms mid summer · medium shade tolerance · to −43 °FAmerican alpine speedwell1 ft · blooms summer · medium shade tolerance · to −28 °FAmerican bistort1.5 ft · blooms mid spring · high shade tolerance · to −38 °FAmerican century plant6 ft · blooms indeterminate · high shade tolerance · to 12 °F

Grasses 153

alkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Falkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °Falpine timothy1.4 ft · blooms late spring · medium shade tolerance · to −43 °Fanalogue sedge1.5 ft · blooms late spring · medium shade tolerance · to −38 °FArizona cottontop4 ft · blooms late summer · high shade tolerance · to −13 °FArizona fescue2 ft · blooms late spring · high shade tolerance · to −23 °F

Vines 1

western white clematis1 ft · blooms mid summer · medium shade tolerance · to −38 °F

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 85285 is Avondale — 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 matter1.5%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classPrime farmland if irrigated and either protected from flooding or not frequently flooded during the growing seasonUSDA classification

Map unit: Avondale 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 85285; 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

30°40°50°60°70°80°90°100°110°120°32 °FJanuary: average high 71 °F, low 39 °F 71°39° JanFebruary: average high 74 °F, low 41 °F 74°41° FebMarch: average high 80 °F, low 46 °F 80°46° MarApril: average high 87 °F, low 51 °F 87°51° AprMay: average high 95 °F, low 59 °F 95°59° MayJune: average high 104 °F, low 67 °F 104°67° JunJuly: average high 106 °F, low 76 °F 106°76° JulAugust: average high 105 °F, low 75 °F 105°75° AugSeptember: average high 101 °F, low 69 °F 101°69° SepOctober: average high 91 °F, low 56 °F 91°56° OctNovember: average high 79 °F, low 45 °F 79°45° NovDecember: average high 69 °F, low 38 °F 69°38° Dec

Precipitation by month inches

0″1″2″January: 1.04 in precipitation 1.0 JanFebruary: 1.12 in precipitation 1.1 FebMarch: 0.96 in precipitation 1.0 MarApril: 0.23 in precipitation 0.2 AprMay: 0.18 in precipitation 0.2 MayJune: 0.06 in precipitation 0.1 JunJuly: 0.99 in precipitation 1.0 JulAugust: 1.30 in precipitation 1.3 AugSeptember: 0.71 in precipitation 0.7 SepOctober: 0.61 in precipitation 0.6 OctNovember: 0.65 in precipitation 0.7 NovDecember: 0.95 in precipitation 0.9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Tempe Asu, AZ (within 1 mile); precipitation: Tempe Asu, AZ (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

852809b
Tempe, AZ · 2 mi
852819b
Tempe, AZ · 2 mi
8528210a
Tempe, AZ · 2 mi
852889b
Tempe, AZ · 2 mi
8520210a
Mesa, AZ · 3 mi
852579b
Scottsdale, AZ · 3 mi
852019b
Mesa, AZ · 4 mi
852839b
Tempe, AZ · 4 mi

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

Questions about 85285

What planting zone is ZIP code 85285?

ZIP code 85285 (Tempe, AZ) is in USDA hardiness zone 10a on the 2023 map: the coldest night of an average winter reaches 30 to 35 °F (−1.1 to 1.7 °C).

When is the last frost in Tempe, AZ?

The median last spring frost (32 °F) near 85285 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 85285 is December 5, giving a median frost-free growing season of 298 days.

When should I plant tomatoes in 85285?

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 85285 get?

About 8.8 inches of precipitation a year (NOAA 1991–2020 normals, Tempe Asu 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 85285 have?

The USDA soil survey maps Avondale at the center of ZIP 85285: clay loam, well drained, pH about 8.2 (alkaline).

Did spring come early in Tempe, AZ in 2026?

Spring leaf-out near 85285 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 85285 is 14 h 22 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 85285 change?

Yes. The 2012 USDA map put 85285 in zone 9b; the 2023 map puts it in zone 10a. The newer map uses 1991–2020 data and more weather stations.