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

Planting zone for 85748 — Tucson, AZ

ZIP code 85748 (Tucson, Pima County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is January 26 and the first fall frost December 16.

Where ZIP 85748 is

Outlined: the ZIP code area · 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.

Zone9a20 to 25 °F
Coldest night−6.7 to −3.9 °C
Last frostJan 26
First frostDec 16
2012 zone9a

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 9a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Tucson, 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 Tucson, AZ

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJanuary 26median — 50% chance of a later frost
Safe for tender plantsFebruary 25only 10% chance of frost after
First fall frostDecember 16median — 10% chance by Nov 26
Growing season326 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 7 and returns around December 28.

From the NOAA station Saguaro Np, AZ — 3 miles away, elevation 3,081 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 85748

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Dec 15 – Dec 29
SpinachSow outdoors · Dec 15 – Jan 5
Broccoli, cabbageStart indoors · Nov 17 – Dec 1
Broccoli, cabbageTransplant · Jan 5 – Jan 19
Onion setsPlant outdoors · Dec 29 – Jan 12
PotatoesPlant outdoors · Jan 5 – Jan 19
LettuceSow outdoors · Dec 29 – Jan 12
Carrots, beetsSow outdoors · Jan 5 – Jan 19
TomatoesStart indoors · Dec 1 – Dec 15
TomatoesTransplant · Feb 2 – Feb 16
Peppers, eggplantStart indoors · Nov 17 – Dec 1
Peppers, eggplantTransplant · Feb 9 – Feb 23
BeansSow outdoors · Feb 2 – Feb 16
Sweet cornSow outdoors · Feb 2 – Feb 16
Cucumbers, squashSow outdoors · Feb 2 – Feb 16
Fall lettuce, spinachSow outdoors · Oct 21 – Nov 4
GarlicPlant cloves · Dec 2 – Jan 6
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jan 26) and first fall frost (Dec 16) 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 85748 came on Jan 23 — 3 days earlier than the 1991–2020 average (Jan 26).

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 9a in Arizona

492 plants native to the lower 48 states, recorded in Arizona, and rated by the USDA to survive 20 °F or colder — the bottom of zone 9a. Each links to its USDA PLANTS profile.

Trees 26

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 109

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 197

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 151

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 Tucson, AZ.

Soil in Tucson, AZ

The soil mapped at the center of ZIP 85748 is Pinaleno — very cobbly sandy loam, well drained.

TextureVery cobbly sandy loamdrains and warms fast; dries out and needs more feeding
pH7.2neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Pinaleno-Stagecoach complex, 5 to 16 percent slopes.

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 85748; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Tucson, AZ

Summer high101 °Faverage high, June
Winter low41 °Faverage low, January
Hot days150days a year at 90 °F or more
Freezing nights8nights a year at 32 °F or less
Growing degree days7,487base 50 °F — the season’s usable heat
Longest day14 h 16 mindaylight on June 21
Shortest day10 h 02 mindaylight on December 21
Onions to growShort-daysummer days stay under about 14 h 20 min, so long-day varieties won’t bulb
Precipitation13.3 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°110°32 °FJanuary: average high 65 °F, low 41 °F 65°41° JanFebruary: average high 68 °F, low 43 °F 68°43° FebMarch: average high 74 °F, low 48 °F 74°48° MarApril: average high 82 °F, low 54 °F 82°54° AprMay: average high 91 °F, low 62 °F 91°62° MayJune: average high 101 °F, low 72 °F 101°72° JunJuly: average high 100 °F, low 74 °F 100°74° JulAugust: average high 98 °F, low 73 °F 98°73° AugSeptember: average high 94 °F, low 69 °F 94°69° SepOctober: average high 86 °F, low 59 °F 86°59° OctNovember: average high 75 °F, low 49 °F 75°49° NovDecember: average high 65 °F, low 41 °F 65°41° Dec

Precipitation by month inches

0″1″2″3″4″January: 1.11 in precipitation 1.1 JanFebruary: 1.24 in precipitation 1.2 FebMarch: 0.67 in precipitation 0.7 MarApril: 0.28 in precipitation 0.3 AprMay: 0.24 in precipitation 0.2 MayJune: 0.31 in precipitation 0.3 JunJuly: 3.14 in precipitation 3.1 JulAugust: 2.41 in precipitation 2.4 AugSeptember: 1.30 in precipitation 1.3 SepOctober: 0.75 in precipitation 0.8 OctNovember: 0.63 in precipitation 0.6 NovDecember: 1.18 in precipitation 1.2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Saguaro Np, AZ (3 mi away); precipitation: Tucson 10.8 E, AZ (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

857309a
Tucson, AZ · 3 mi
857109b
Tucson, AZ · 4 mi
857499a
Tucson, AZ · 5 mi
857159b
Tucson, AZ · 5 mi
857089b
Tucson, AZ · 7 mi
857119b
Tucson, AZ · 8 mi
857509a
Tucson, AZ · 8 mi
857129b
Tucson, AZ · 8 mi

All 53 ZIP codes in Tucson → · Arizona planting zones →

Questions about 85748

What planting zone is ZIP code 85748?

ZIP code 85748 (Tucson, AZ) is in USDA hardiness zone 9a on the 2023 map: the coldest night of an average winter reaches 20 to 25 °F (−6.7 to −3.9 °C).

When is the last frost in Tucson, AZ?

The median last spring frost (32 °F) near 85748 is January 26; after February 25 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Saguaro Np station.

When is the first frost in Tucson, AZ?

The median first fall frost near 85748 is December 16, giving a median frost-free growing season of 326 days.

When should I plant tomatoes in 85748?

Start tomato seeds indoors around Dec 1 – Dec 15 and set transplants outside around Feb 2 – Feb 16, one to three weeks after the median last frost.

How much rain and snow does 85748 get?

About 13.3 inches of precipitation a year (NOAA 1991–2020 normals, Tucson 10.8 E station).

How hot do summers get in Tucson, AZ?

The average high peaks at 101 °F in June, with about 150 days a year at 90 °F or more.

What kind of soil does 85748 have?

The USDA soil survey maps Pinaleno at the center of ZIP 85748: very cobbly sandy loam, well drained, pH about 7.2 (neutral).

Did spring come early in Tucson, AZ in 2026?

Spring leaf-out near 85748 came on Jan 23 in 2026, 3 days earlier than the 1991–2020 average (Jan 26), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Tucson, AZ?

Short-day onions: the longest day near 85748 is 14 h 16 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.