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

Planting zone for Casa Grande, AZ

Casa Grande, AZ is in USDA zone 9a across its 4 ZIP codes. The median last spring frost is February 5 and the first fall frost December 6.

Casa Grande on the zone map

Outlined: its 3 ZIP code areas · 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
ZIP codes4
Last frostFeb 5
First frostDec 6
Growing season305 days

9a 4 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Casa Grande, 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 Casa Grande, AZ

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostFebruary 5median — 50% chance of a later frost
Safe for tender plantsFebruary 28only 10% chance of frost after
First fall frostDecember 6median — 10% chance by Nov 18
Growing season305 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 14 and returns around December 22.

From the NOAA station Casa Grande, AZ, 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 Casa Grande

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Dec 25 – Jan 8
SpinachSow outdoors · Dec 25 – Jan 15
Broccoli, cabbageStart indoors · Nov 27 – Dec 11
Broccoli, cabbageTransplant · Jan 15 – Jan 29
Onion setsPlant outdoors · Jan 8 – Jan 22
PotatoesPlant outdoors · Jan 15 – Jan 29
LettuceSow outdoors · Jan 8 – Jan 22
Carrots, beetsSow outdoors · Jan 15 – Jan 29
TomatoesStart indoors · Dec 11 – Dec 25
TomatoesTransplant · Feb 12 – Feb 26
Peppers, eggplantStart indoors · Nov 27 – Dec 11
Peppers, eggplantTransplant · Feb 19 – Mar 5
BeansSow outdoors · Feb 12 – Feb 26
Sweet cornSow outdoors · Feb 12 – Feb 26
Cucumbers, squashSow outdoors · Feb 12 – Feb 26
Fall lettuce, spinachSow outdoors · Oct 11 – Oct 25
GarlicPlant cloves · Nov 22 – Dec 27
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 5) and first fall frost (Dec 6) 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 85130 came on Jan 25 — about the same time as 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 Casa Grande, AZ.

Soil in Casa Grande, AZ

The soil mapped at the center of ZIP 85130 is Vaiva — extremely stony sandy loam, somewhat excessively drained.

TextureExtremely stony sandy loamdrains and warms fast; dries out and needs more feeding
pH7.9alkaline; most vegetables like 6.0–7.0
DrainageSomewhat excessively drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Vaiva-Rock outcrop complex, 15 to 50 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 85130; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Casa Grande, AZ

Summer high106 °Faverage high, June
Winter low37 °Faverage low, December
Hot days176days a year at 90 °F or more
Freezing nights18nights a year at 32 °F or less
Growing degree days7,917base 50 °F — the season’s usable heat
Longest day14 h 19 mindaylight on June 21
Shortest day9 h 59 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation8.5 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 67 °F, low 38 °F 67°38° JanFebruary: average high 71 °F, low 42 °F 71°42° FebMarch: average high 80 °F, low 47 °F 80°47° MarApril: average high 87 °F, low 52 °F 87°52° AprMay: average high 95 °F, low 60 °F 95°60° MayJune: average high 106 °F, low 69 °F 106°69° JunJuly: average high 105 °F, low 76 °F 105°76° JulAugust: average high 104 °F, low 75 °F 104°75° AugSeptember: average high 99 °F, low 69 °F 99°69° SepOctober: average high 89 °F, low 57 °F 89°57° OctNovember: average high 76 °F, low 45 °F 76°45° NovDecember: average high 65 °F, low 37 °F 65°37° Dec

Precipitation by month inches

0″1″2″January: 1.02 in precipitation 1.0 JanFebruary: 1.06 in precipitation 1.1 FebMarch: 0.81 in precipitation 0.8 MarApril: 0.26 in precipitation 0.3 AprMay: 0.18 in precipitation 0.2 MayJune: 0.16 in precipitation 0.2 JunJuly: 1.04 in precipitation 1.0 JulAugust: 1.22 in precipitation 1.2 AugSeptember: 0.73 in precipitation 0.7 SepOctober: 0.64 in precipitation 0.6 OctNovember: 0.45 in precipitation 0.5 NovDecember: 0.91 in precipitation 0.9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Robson Rch, AZ (4 mi away); precipitation: Casa Grande 5.7 Se, AZ (within 1 mile). Daylight is calculated from latitude.

ZIP codes in Casa Grande

851229a
20 to 25 °F
851309a
20 to 25 °F
851939a
20 to 25 °F
851949a
20 to 25 °F

Arizona planting zones →

Questions about Casa Grande

What planting zone is Casa Grande, AZ?

Casa Grande, AZ is in USDA hardiness zone 9a on the 2023 map (9a: 20 to 25 °F).

When is the last frost in Casa Grande, AZ?

The median last spring frost is February 5 and the median first fall frost is December 6 (NOAA 1991–2020 normals, Casa Grande station).

When can I plant a garden in Casa Grande, AZ?

Cool-season crops like peas and spinach go in around Dec 25 – Jan 15; tomatoes, peppers, beans and squash after about Feb 12, once frost risk has passed.

What kind of onions grow in Casa Grande, AZ?

Intermediate onions: the longest day is 14 h 19 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

How much rain and snow does Casa Grande, AZ get?

About 8.5 inches of precipitation a year (NOAA 1991–2020 normals).