Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 30, 2026

Planting zone for Willcox, AZ

Willcox, AZ is in USDA zones 8a to 8b across its 2 ZIP codes. The median last spring frost is April 9 and the first fall frost October 31.

Willcox on the zone map

Outlined: its 1 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.

Zones8a–8b10 to 20 °F

ZIP codes2

Last frostApr 9

First frostOct 31

Growing season204 days

8a 1 ZIP 8b 1 ZIP

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Willcox, 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 Willcox, AZ

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 9median — 50% chance of a later frost

Safe for tender plantsApril 29only 10% chance of frost after

First fall frostOctober 31median — 10% chance by Oct 20

Growing season204 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 16 and returns around November 12.

From the NOAA station Willcox, AZ, elevation 4,170 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 Willcox

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 26 – Mar 12

SpinachSow outdoors · Feb 26 – Mar 19

Broccoli, cabbageStart indoors · Jan 29 – Feb 12

Broccoli, cabbageTransplant · Mar 19 – Apr 2

Onion setsPlant outdoors · Mar 12 – Mar 26

PotatoesPlant outdoors · Mar 19 – Apr 2

LettuceSow outdoors · Mar 12 – Mar 26

Carrots, beetsSow outdoors · Mar 19 – Apr 2

TomatoesStart indoors · Feb 12 – Feb 26

TomatoesTransplant · Apr 16 – Apr 30

Peppers, eggplantStart indoors · Jan 29 – Feb 12

Peppers, eggplantTransplant · Apr 23 – May 7

BeansSow outdoors · Apr 16 – Apr 30

Sweet cornSow outdoors · Apr 16 – Apr 30

Cucumbers, squashSow outdoors · Apr 16 – Apr 30

Fall lettuce, spinachSow outdoors · Sep 5 – Sep 19

GarlicPlant cloves · Oct 17 – Nov 21

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 9) and first fall frost (Oct 31) 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 85643 came on Feb 5 — about the same time as the 1991–2020 average (Feb 4).

average
Feb 42026
Feb 5

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 8a in Arizona

472 plants native to the lower 48 states, recorded in Arizona, and rated by the USDA to survive 10 °F or colder — the bottom of zone 8a. 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 Willcox, AZ.

Soil in Willcox, AZ

The soil mapped at the center of ZIP 85643 is Sonoita — sandy loam, well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding

pH6.7neutral; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter0.75%low — add compost

Hydrologic groupAwater soaks in fast

Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Sonoita sandy loam, 0 to 2 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 85643; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Willcox, AZ

Summer high97 °Faverage high, June

Winter low28 °Faverage low, January

Hot days119days a year at 90 °F or more

Freezing nights93nights a year at 32 °F or less

Growing degree days5,044base 50 °F — the season’s usable heat

Longest day14 h 17 mindaylight on June 21

Shortest day10 h 01 mindaylight on December 21

Onions to growShort-daysummer days stay under about 14 h 20 min, so long-day varieties won’t bulb

Precipitation12.4 inper year, rain and melted snow

Snowfall2 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Willcox, AZ (17 mi away); precipitation: Willcox, AZ (17 mi away). Daylight is calculated from latitude.

ZIP codes in Willcox

Arizona planting zones →

Questions about Willcox

What planting zone is Willcox, AZ?

Willcox, AZ is in USDA hardiness zones 8a to 8b on the 2023 map (8a: 10 to 15 °F; 8b: 15 to 20 °F).

When is the last frost in Willcox, AZ?

The median last spring frost is April 9 and the median first fall frost is October 31 (NOAA 1991–2020 normals, Willcox station).

When can I plant a garden in Willcox, AZ?

Cool-season crops like peas and spinach go in around Feb 26 – Mar 19; tomatoes, peppers, beans and squash after about Apr 16, once frost risk has passed.

What kind of onions grow in Willcox, AZ?

Short-day onions: the longest day is 14 h 17 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

How much rain and snow does Willcox, AZ get?

About 12.4 inches of precipitation a year and 2 inches of snowfall (NOAA 1991–2020 normals).