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

Planting zone for 85190 — Tortilla Flat, AZ

ZIP code 85190 (Tortilla Flat, Maricopa County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F.

Where ZIP 85190 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 frostrare
First frostrare
2012 zone9b

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 9b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Tortilla Flat, 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 Mormon Flat, AZ — 4 miles away, elevation 1,706 ft) the median growing season is 334 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 85190 came on Jan 20 — 4 days earlier than the 1991–2020 average (Jan 24).

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.

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 113

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 152

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 Tortilla Flat, AZ.

Soil in Tortilla Flat, AZ

The soil mapped at the center of ZIP 85190 is Ustic Haplargids — extremely gravelly sandy loam, well drained.

TextureExtremely gravelly sandy loamdrains and warms fast; dries out and needs more feeding
pH5.8moderately acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1.5%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Ustic Haplargids and Typic Torriorthents; cool thermic aridic fan piedmonts.

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 85190; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Tortilla Flat, AZ

Summer high106 °Faverage high, July
Winter low44 °Faverage low, January
Hot days170days a year at 90 °F or more
Freezing nights3nights a year at 32 °F or less
Growing degree days8,553base 50 °F — the season’s usable heat
Longest day14 h 23 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
Precipitation12 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 68 °F, low 44 °F 68°44° JanFebruary: average high 70 °F, low 45 °F 70°45° FebMarch: average high 77 °F, low 50 °F 77°50° MarApril: average high 85 °F, low 55 °F 85°55° AprMay: average high 94 °F, low 64 °F 94°64° MayJune: average high 104 °F, low 73 °F 104°73° JunJuly: average high 106 °F, low 80 °F 106°80° JulAugust: average high 104 °F, low 79 °F 104°79° AugSeptember: average high 98 °F, low 74 °F 98°74° SepOctober: average high 89 °F, low 63 °F 89°63° OctNovember: average high 75 °F, low 52 °F 75°52° NovDecember: average high 65 °F, low 44 °F 65°44° Dec

Precipitation by month inches

0″1″2″January: 1.92 in precipitation 1.9 JanFebruary: 1.48 in precipitation 1.5 FebMarch: 1.72 in precipitation 1.7 MarApril: 0.47 in precipitation 0.5 AprMay: 0.28 in precipitation 0.3 MayJune: 0.04 in precipitation 0.0 JunJuly: 1.32 in precipitation 1.3 JulAugust: 1.41 in precipitation 1.4 AugSeptember: 0.48 in precipitation 0.5 SepOctober: 0.74 in precipitation 0.7 OctNovember: 0.42 in precipitation 0.4 NovDecember: 1.72 in precipitation 1.7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Mormon Flat, AZ (4 mi away); precipitation: Mormon Flat, AZ (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 9b.

852159b
Mesa, AZ · 11 mi
851189b
Gold Canyon, AZ · 12 mi
851199b
Apache Junction, AZ · 12 mi
851789b
Apache Junction, AZ · 12 mi
852649b
Fort Mcdowell, AZ · 13 mi
851209b
Apache Junction, AZ · 14 mi
851179b
Apache Junction, AZ · 14 mi
855459b
Roosevelt, AZ · 15 mi

Arizona planting zones →

Questions about 85190

What planting zone is ZIP code 85190?

ZIP code 85190 (Tortilla Flat, 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).

How much rain and snow does 85190 get?

About 12 inches of precipitation a year (NOAA 1991–2020 normals, Mormon Flat station).

How hot do summers get in Tortilla Flat, AZ?

The average high peaks at 106 °F in July, with about 170 days a year at 90 °F or more.

What kind of soil does 85190 have?

The USDA soil survey maps Ustic Haplargids at the center of ZIP 85190: extremely gravelly sandy loam, well drained, pH about 5.8 (moderately acidic).

Did spring come early in Tortilla Flat, AZ in 2026?

Spring leaf-out near 85190 came on Jan 20 in 2026, 4 days earlier than the 1991–2020 average (Jan 24), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Tortilla Flat, AZ?

Intermediate onions: the longest day near 85190 is 14 h 23 min, so day-neutral types bulb best; long-day varieties may not bulb fully.