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

Planting zone for 85543 — Pima, AZ

ZIP code 85543 (Pima, Graham County) is in USDA zone 8b: the coldest winter night averages 15 to 20 °F. The median last spring frost is April 1 and the first fall frost November 6.

Where ZIP 85543 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 1
First frostNov 6
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 Pima, 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 Pima, AZ

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 1median — 50% chance of a later frost
Safe for tender plantsApril 18only 10% chance of frost after
First fall frostNovember 6median — 10% chance by Oct 21
Growing season217 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 13 and returns around November 16.

From the NOAA station Ft Thomas 2 Sw, AZ — 6 miles away, elevation 2,835 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 85543

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 18 – Mar 4
SpinachSow outdoors · Feb 18 – Mar 11
Broccoli, cabbageStart indoors · Jan 21 – Feb 4
Broccoli, cabbageTransplant · Mar 11 – Mar 25
Onion setsPlant outdoors · Mar 4 – Mar 18
PotatoesPlant outdoors · Mar 11 – Mar 25
LettuceSow outdoors · Mar 4 – Mar 18
Carrots, beetsSow outdoors · Mar 11 – Mar 25
TomatoesStart indoors · Feb 4 – Feb 18
TomatoesTransplant · Apr 8 – Apr 22
Peppers, eggplantStart indoors · Jan 21 – Feb 4
Peppers, eggplantTransplant · Apr 15 – Apr 29
BeansSow outdoors · Apr 8 – Apr 22
Sweet cornSow outdoors · Apr 8 – Apr 22
Cucumbers, squashSow outdoors · Apr 8 – Apr 22
Fall lettuce, spinachSow outdoors · Sep 11 – Sep 25
GarlicPlant cloves · Oct 23 – Nov 27
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 1) and first fall frost (Nov 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 85543 came on Jan 31 — 3 days earlier than the 1991–2020 average (Feb 3).

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).

Soil in Pima, AZ

The soil mapped at the center of ZIP 85543 is Grabe — clay loam, well drained.

TextureClay loamholds water and nutrients; slow to drain and warm up
pH7.9alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1.5%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classPrime farmland if irrigated and either protected from flooding or not frequently flooded during the growing seasonUSDA classification

Map unit: Grabe clay loam.

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 85543; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Pima, AZ

Summer high100 °Faverage high, June
Winter low28 °Faverage low, January
Hot days136days a year at 90 °F or more
Freezing nights82nights a year at 32 °F or less
Growing degree days5,841base 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
Precipitation10.2 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°100°110°32 °FJanuary: average high 61 °F, low 28 °F 61°28° JanFebruary: average high 66 °F, low 32 °F 66°32° FebMarch: average high 74 °F, low 37 °F 74°37° MarApril: average high 82 °F, low 44 °F 82°44° AprMay: average high 91 °F, low 53 °F 91°53° MayJune: average high 100 °F, low 62 °F 100°62° JunJuly: average high 100 °F, low 71 °F 100°71° JulAugust: average high 98 °F, low 69 °F 98°69° AugSeptember: average high 93 °F, low 62 °F 93°62° SepOctober: average high 84 °F, low 48 °F 84°48° OctNovember: average high 71 °F, low 35 °F 71°35° NovDecember: average high 60 °F, low 28 °F 60°28° Dec

Precipitation by month inches

0″1″2″January: 1.01 in precipitation 1.0 JanFebruary: 0.98 in precipitation 1.0 FebMarch: 0.60 in precipitation 0.6 MarApril: 0.25 in precipitation 0.3 AprMay: 0.37 in precipitation 0.4 MayJune: 0.15 in precipitation 0.1 JunJuly: 1.74 in precipitation 1.7 JulAugust: 1.85 in precipitation 1.9 AugSeptember: 1.10 in precipitation 1.1 SepOctober: 0.73 in precipitation 0.7 OctNovember: 0.50 in precipitation 0.5 NovDecember: 0.92 in precipitation 0.9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Ft Thomas 2 Sw, AZ (6 mi away); precipitation: Ft Thomas 2 Sw, AZ (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 8b.

855358b
Eden, AZ · 2 mi
855318b
Central, AZ · 9 mi
855528b
Thatcher, AZ · 11 mi
855488b
Safford, AZ · 14 mi
855368b
Fort Thomas, AZ · 14 mi
855308b
Bylas, AZ · 23 mi
855518b
Solomon, AZ · 25 mi
855468b
Safford, AZ · 25 mi

Arizona planting zones →

Questions about 85543

What planting zone is ZIP code 85543?

ZIP code 85543 (Pima, 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 Pima, AZ?

The median last spring frost (32 °F) near 85543 is April 1; after April 18 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Ft Thomas 2 Sw station.

When is the first frost in Pima, AZ?

The median first fall frost near 85543 is November 6, giving a median frost-free growing season of 217 days.

When should I plant tomatoes in 85543?

Start tomato seeds indoors around Feb 4 – Feb 18 and set transplants outside around Apr 8 – Apr 22, one to three weeks after the median last frost.

How much rain and snow does 85543 get?

About 10.2 inches of precipitation a year (NOAA 1991–2020 normals, Ft Thomas 2 Sw station).

How hot do summers get in Pima, AZ?

The average high peaks at 100 °F in June, with about 136 days a year at 90 °F or more.

What kind of soil does 85543 have?

The USDA soil survey maps Grabe at the center of ZIP 85543: clay loam, well drained, pH about 7.9 (alkaline).

Did spring come early in Pima, AZ in 2026?

Spring leaf-out near 85543 came on Jan 31 in 2026, 3 days earlier than the 1991–2020 average (Feb 3), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Pima, AZ?

Intermediate onions: the longest day near 85543 is 14 h 20 min, so day-neutral types bulb best; long-day varieties may not bulb fully.