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

Planting zone for 85540 — Morenci, AZ

ZIP code 85540 (Morenci, Greenlee County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is February 26 and the first fall frost November 23.

Where ZIP 85540 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.

Zone8b15 to 20 °F

Coldest night−9.4 to −6.7 °C

Last frostFeb 26

First frostNov 23

2012 zone9a

Was 9a on the 2012 map — half a zone colder now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 8b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Morenci, 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 Morenci, AZ

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostFebruary 26median — 50% chance of a later frost

Safe for tender plantsMarch 15only 10% chance of frost after

First fall frostNovember 23median — 10% chance by Nov 10

Growing season268 daysfrost-free, median

A hard freeze (28 °F) usually ends around February 5 and returns around December 5.

From the NOAA station Clifton, AZ — 6 miles away, elevation 3,521 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 85540

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Jan 15 – Jan 29

SpinachSow outdoors · Jan 15 – Feb 5

Broccoli, cabbageStart indoors · Dec 18 – Jan 1

Broccoli, cabbageTransplant · Feb 5 – Feb 19

Onion setsPlant outdoors · Jan 29 – Feb 12

PotatoesPlant outdoors · Feb 5 – Feb 19

LettuceSow outdoors · Jan 29 – Feb 12

Carrots, beetsSow outdoors · Feb 5 – Feb 19

TomatoesStart indoors · Jan 1 – Jan 15

TomatoesTransplant · Mar 5 – Mar 19

Peppers, eggplantStart indoors · Dec 18 – Jan 1

Peppers, eggplantTransplant · Mar 12 – Mar 26

BeansSow outdoors · Mar 5 – Mar 19

Sweet cornSow outdoors · Mar 5 – Mar 19

Cucumbers, squashSow outdoors · Mar 5 – Mar 19

Fall lettuce, spinachSow outdoors · Sep 28 – Oct 12

GarlicPlant cloves · Nov 9 – Dec 14

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 26) and first fall frost (Nov 23) 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 85540 came on Feb 1 — about the same time as the 1991–2020 average (Feb 3).

average
Feb 32026
Feb 1

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 8b in Arizona

482 plants native to the lower 48 states, recorded in Arizona, and rated by the USDA to survive 15 °F or colder — the bottom of zone 8b. 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 Morenci, AZ.

Soil in Morenci, AZ

The soil mapped at the center of ZIP 85540 is Limpia — extremely cobbly clay loam, well drained.

TextureExtremely cobbly clay loamholds water and nutrients; slow to drain and warm up

pH7.5slightly alkaline; 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: Limpia-Graham-Rock outcrop complex, 9 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 85540; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Morenci, AZ

Summer high100 °Faverage high, June

Winter low35 °Faverage low, January

Hot days135days a year at 90 °F or more

Freezing nights30nights a year at 32 °F or less

Growing degree days6,621base 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

Precipitation17 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: Clifton, AZ (6 mi away); precipitation: Clifton, AZ (6 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.

Mule Creek, NM · 27 mi

855528b

Thatcher, AZ · 27 mi

Arizona planting zones →

Questions about 85540

What planting zone is ZIP code 85540?

ZIP code 85540 (Morenci, AZ) is in USDA hardiness zone 8b on the 2023 map: the coldest night of an average winter reaches 15 to 20 °F (−9.4 to −6.7 °C).

When is the last frost in Morenci, AZ?

The median last spring frost (32 °F) near 85540 is February 26; after March 15 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Clifton station.

When is the first frost in Morenci, AZ?

The median first fall frost near 85540 is November 23, giving a median frost-free growing season of 268 days.

When should I plant tomatoes in 85540?

Start tomato seeds indoors around Jan 1 – Jan 15 and set transplants outside around Mar 5 – Mar 19, one to three weeks after the median last frost.

How much rain and snow does 85540 get?

About 17 inches of precipitation a year (NOAA 1991–2020 normals, Clifton station).

How hot do summers get in Morenci, AZ?

The average high peaks at 100 °F in June, with about 135 days a year at 90 °F or more.

What kind of soil does 85540 have?

The USDA soil survey maps Limpia at the center of ZIP 85540: extremely cobbly clay loam, well drained, pH about 7.5 (slightly alkaline).

Did spring come early in Morenci, AZ in 2026?

Spring leaf-out near 85540 came on Feb 1 in 2026, about the same as the 1991–2020 average (Feb 3), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Morenci, AZ?

Intermediate onions: the longest day near 85540 is 14 h 20 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 85540 change?

Yes. The 2012 USDA map put 85540 in zone 9a; the 2023 map puts it in zone 8b. The newer map uses 1991–2020 data and more weather stations.