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

Planting zone for 85191 — Valley Farms, AZ

ZIP code 85191 (Valley Farms, Pinal County) is in USDA zone 9a: the coldest winter night averages 20 to 25 °F. The median last spring frost is January 30 and the first fall frost December 12.

Where ZIP 85191 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 30
First frostDec 12
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 Valley Farms, 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 Valley Farms, AZ

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJanuary 30median — 50% chance of a later frost
Safe for tender plantsFebruary 24only 10% chance of frost after
First fall frostDecember 12median — 10% chance by Nov 22
Growing season319 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 8 and returns around December 26.

From the NOAA station Florence, AZ — 5 miles away, elevation 1,401 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 85191

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Dec 19 – Jan 2
SpinachSow outdoors · Dec 19 – Jan 9
Broccoli, cabbageStart indoors · Nov 21 – Dec 5
Broccoli, cabbageTransplant · Jan 9 – Jan 23
Onion setsPlant outdoors · Jan 2 – Jan 16
PotatoesPlant outdoors · Jan 9 – Jan 23
LettuceSow outdoors · Jan 2 – Jan 16
Carrots, beetsSow outdoors · Jan 9 – Jan 23
TomatoesStart indoors · Dec 5 – Dec 19
TomatoesTransplant · Feb 6 – Feb 20
Peppers, eggplantStart indoors · Nov 21 – Dec 5
Peppers, eggplantTransplant · Feb 13 – Feb 27
BeansSow outdoors · Feb 6 – Feb 20
Sweet cornSow outdoors · Feb 6 – Feb 20
Cucumbers, squashSow outdoors · Feb 6 – Feb 20
Fall lettuce, spinachSow outdoors · Oct 17 – Oct 31
GarlicPlant cloves · Nov 28 – Jan 2
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jan 30) and first fall frost (Dec 12) 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 85191 came on Jan 25 — about the same time as the 1991–2020 average (Jan 25).

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 Valley Farms, AZ.

Soil in Valley Farms, AZ

The soil mapped at the center of ZIP 85191 is Mohall — sandy loam, well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding
pH8.2alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Mohall sandy loam, 0 to 1 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 85191; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Valley Farms, AZ

Summer high105 °Faverage high, July
Winter low41 °Faverage low, December
Hot days169days a year at 90 °F or more
Freezing nights10nights a year at 32 °F or less
Growing degree days8,251base 50 °F — the season’s usable heat
Longest day14 h 20 mindaylight on June 21
Shortest day9 h 58 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation8.6 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 42 °F 68°42° JanFebruary: average high 71 °F, low 44 °F 71°44° FebMarch: average high 79 °F, low 49 °F 79°49° MarApril: average high 86 °F, low 53 °F 86°53° AprMay: average high 94 °F, low 61 °F 94°61° MayJune: average high 103 °F, low 70 °F 103°70° JunJuly: average high 105 °F, low 78 °F 105°78° JulAugust: average high 103 °F, low 78 °F 103°78° AugSeptember: average high 99 °F, low 72 °F 99°72° SepOctober: average high 89 °F, low 60 °F 89°60° OctNovember: average high 77 °F, low 48 °F 77°48° NovDecember: average high 67 °F, low 41 °F 67°41° Dec

Precipitation by month inches

0″1″2″January: 1.41 in precipitation 1.4 JanFebruary: 0.94 in precipitation 0.9 FebMarch: 1.22 in precipitation 1.2 MarApril: 0.25 in precipitation 0.3 AprMay: 0.36 in precipitation 0.4 MayJune: 0.04 in precipitation 0.0 JunJuly: 1.18 in precipitation 1.2 JulAugust: 1.08 in precipitation 1.1 AugSeptember: 0.28 in precipitation 0.3 SepOctober: 0.45 in precipitation 0.5 OctNovember: 0.45 in precipitation 0.5 NovDecember: 0.98 in precipitation 1.0 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Florence, AZ (5 mi away); precipitation: Florence, AZ (5 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

851289a
Coolidge, AZ · 4 mi
851949a
Casa Grande, AZ · 12 mi
851439b
San Tan Valley, AZ · 13 mi
851329b
Florence, AZ · 14 mi
851479a
Sacaton, AZ · 18 mi
851229a
Casa Grande, AZ · 18 mi
851409b
San Tan Valley, AZ · 18 mi
851309a
Casa Grande, AZ · 19 mi

Arizona planting zones →

Questions about 85191

What planting zone is ZIP code 85191?

ZIP code 85191 (Valley Farms, 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 Valley Farms, AZ?

The median last spring frost (32 °F) near 85191 is January 30; after February 24 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Florence station.

When is the first frost in Valley Farms, AZ?

The median first fall frost near 85191 is December 12, giving a median frost-free growing season of 319 days.

When should I plant tomatoes in 85191?

Start tomato seeds indoors around Dec 5 – Dec 19 and set transplants outside around Feb 6 – Feb 20, one to three weeks after the median last frost.

How much rain and snow does 85191 get?

About 8.6 inches of precipitation a year (NOAA 1991–2020 normals, Florence station).

How hot do summers get in Valley Farms, AZ?

The average high peaks at 105 °F in July, with about 169 days a year at 90 °F or more.

What kind of soil does 85191 have?

The USDA soil survey maps Mohall at the center of ZIP 85191: sandy loam, well drained, pH about 8.2 (alkaline).

Did spring come early in Valley Farms, AZ in 2026?

Spring leaf-out near 85191 came on Jan 25 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 Valley Farms, AZ?

Intermediate onions: the longest day near 85191 is 14 h 20 min, so day-neutral types bulb best; long-day varieties may not bulb fully.