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

Planting zone for 85602 — Benson, AZ

ZIP code 85602 (Benson, Cochise County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is April 24 and the first fall frost October 31.

Where ZIP 85602 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 frostApr 24

First frostOct 31

2012 zone8b

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 8b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Benson, 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 Benson, AZ

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 24median — 50% chance of a later frost

Safe for tender plantsMay 9only 10% chance of frost after

First fall frostOctober 31median — 10% chance by Oct 14

Growing season187 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 9 and returns around November 10.

From the NOAA station Cascabel, AZ — 7 miles away, elevation 3,196 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 85602

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 13 – Mar 27

SpinachSow outdoors · Mar 13 – Apr 3

Broccoli, cabbageStart indoors · Feb 13 – Feb 27

Broccoli, cabbageTransplant · Apr 3 – Apr 17

Onion setsPlant outdoors · Mar 27 – Apr 10

PotatoesPlant outdoors · Apr 3 – Apr 17

LettuceSow outdoors · Mar 27 – Apr 10

Carrots, beetsSow outdoors · Apr 3 – Apr 17

TomatoesStart indoors · Feb 27 – Mar 13

TomatoesTransplant · May 1 – May 15

Peppers, eggplantStart indoors · Feb 13 – Feb 27

Peppers, eggplantTransplant · May 8 – May 22

BeansSow outdoors · May 1 – May 15

Sweet cornSow outdoors · May 1 – May 15

Cucumbers, squashSow outdoors · May 1 – May 15

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 24) 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 85602 came on Jan 24 — 8 days earlier than the 1991–2020 average (Feb 1).

average
Feb 12026
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 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 Benson, AZ.

Soil in Benson, AZ

The soil mapped at the center of ZIP 85602 is Mabray — very gravelly loam, well drained.

TextureVery gravelly loama good balance for most vegetables

pH8.2alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter1.2%low — add compost

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Mabray-Rock outcrop complex, 5 to 70 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 85602; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Benson, AZ

Summer high100 °Faverage high, June

Winter low29 °Faverage low, December

Hot days143days a year at 90 °F or more

Freezing nights83nights a year at 32 °F or less

Growing degree days5,338base 50 °F — the season’s usable heat

Longest day14 h 16 mindaylight on June 21

Shortest day10 h 02 mindaylight on December 21

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

Precipitation13 inper year, rain and melted snow

Snowfall1 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Cascabel, AZ (7 mi away); precipitation: Cascabel, AZ (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Saint David, AZ · 24 mi

Arizona planting zones →

Questions about 85602

What planting zone is ZIP code 85602?

ZIP code 85602 (Benson, 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 Benson, AZ?

The median last spring frost (32 °F) near 85602 is April 24; after May 9 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Cascabel station.

When is the first frost in Benson, AZ?

The median first fall frost near 85602 is October 31, giving a median frost-free growing season of 187 days.

When should I plant tomatoes in 85602?

Start tomato seeds indoors around Feb 27 – Mar 13 and set transplants outside around May 1 – May 15, one to three weeks after the median last frost.

How much rain and snow does 85602 get?

About 13 inches of precipitation a year and 1 inches of snowfall (NOAA 1991–2020 normals, Cascabel station).

How hot do summers get in Benson, AZ?

The average high peaks at 100 °F in June, with about 143 days a year at 90 °F or more.

What kind of soil does 85602 have?

The USDA soil survey maps Mabray at the center of ZIP 85602: very gravelly loam, well drained, pH about 8.2 (alkaline).

Did spring come early in Benson, AZ in 2026?

Spring leaf-out near 85602 came on Jan 24 in 2026, 8 days earlier than the 1991–2020 average (Feb 1), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Benson, AZ?

Short-day onions: the longest day near 85602 is 14 h 16 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.