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

Planting zone for 85710 — Tucson, AZ

ZIP code 85710 (Tucson, Pima County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is January 26 and the first fall frost December 16.

Where ZIP 85710 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.

Zone9b25 to 30 °F

Coldest night−3.9 to −1.1 °C

Last frostJan 26

First frostDec 16

2012 zone9a

Was 9a 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 9b 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 — 6 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 85710

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 85710 came on Jan 23 — about the same time as the 1991–2020 average (Jan 25).

average
Jan 252026
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 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 Tucson, AZ.

Soil in Tucson, AZ

The soil mapped at the center of ZIP 85710 is Anthony — fine sandy loam, well drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding

pH7.9alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter0.75%low — add compost

Hydrologic groupAwater soaks in fast

Farmland classNot prime farmlandUSDA classification

Map unit: Anthony fine sandy loam, 0 to 3 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 85710; 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

Precipitation12.6 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: Saguaro Np, AZ (6 mi away); precipitation: Tucson 4.9 E, AZ (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

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

Questions about 85710

What planting zone is ZIP code 85710?

ZIP code 85710 (Tucson, 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 Tucson, AZ?

The median last spring frost (32 °F) near 85710 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 85710 is December 16, giving a median frost-free growing season of 326 days.

When should I plant tomatoes in 85710?

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 85710 get?

About 12.6 inches of precipitation a year (NOAA 1991–2020 normals, Tucson 4.9 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 85710 have?

The USDA soil survey maps Anthony at the center of ZIP 85710: fine sandy loam, well drained, pH about 7.9 (alkaline).

Did spring come early in Tucson, AZ in 2026?

Spring leaf-out near 85710 came on Jan 23 in 2026, about the same as the 1991–2020 average (Jan 25), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Tucson, AZ?

Short-day onions: the longest day near 85710 is 14 h 16 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

Did the zone for 85710 change?

Yes. The 2012 USDA map put 85710 in zone 9a; the 2023 map puts it in zone 9b. The newer map uses 1991–2020 data and more weather stations.