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

Planting zone for 86338 — Skull Valley, AZ

ZIP code 86338 (Skull Valley, Yavapai County) is in USDA zone 8a: the coldest winter night averages 10 to 15 °F. The median last spring frost is April 30 and the first fall frost October 20.

Where ZIP 86338 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.

Zone8a10 to 15 °F
Coldest night−12.2 to −9.4 °C
Last frostApr 30
First frostOct 20
2012 zone8a

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 8a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Skull Valley, 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 Skull Valley, AZ

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 30median — 50% chance of a later frost
Safe for tender plantsMay 15only 10% chance of frost after
First fall frostOctober 20median — 10% chance by Oct 7
Growing season172 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 13 and returns around October 31.

From the NOAA station Prescott, AZ — 19 miles away, elevation 5,207 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 86338

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 19 – Apr 2
SpinachSow outdoors · Mar 19 – Apr 9
Broccoli, cabbageStart indoors · Feb 19 – Mar 5
Broccoli, cabbageTransplant · Apr 9 – Apr 23
Onion setsPlant outdoors · Apr 2 – Apr 16
PotatoesPlant outdoors · Apr 9 – Apr 23
LettuceSow outdoors · Apr 2 – Apr 16
Carrots, beetsSow outdoors · Apr 9 – Apr 23
TomatoesStart indoors · Mar 5 – Mar 19
TomatoesTransplant · May 7 – May 21
Peppers, eggplantStart indoors · Feb 19 – Mar 5
Peppers, eggplantTransplant · May 14 – May 28
BeansSow outdoors · May 7 – May 21
Sweet cornSow outdoors · May 7 – May 21
Cucumbers, squashSow outdoors · May 7 – May 21
Fall lettuce, spinachSow outdoors · Aug 25 – Sep 8
GarlicPlant cloves · Oct 6 – Nov 10
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 30) and first fall frost (Oct 20) 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 86338 came on Feb 3 — 15 days earlier than the 1991–2020 average (Feb 18).

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.

Trees 24

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 100

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 195

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 eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °F

Grasses 144

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 Skull Valley, AZ.

Soil in Skull Valley, AZ

The soil mapped at the center of ZIP 86338 is Barkerville — cobbly sandy loam, well drained.

TextureCobbly sandy loamdrains and warms fast; dries out and needs more feeding
pH7.0neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1.5%low — add compost
Hydrologic groupBwater soaks in moderately
Farmland classNot prime farmlandUSDA classification

Map unit: Barkerville cobbly sandy loam, 20 to 60 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 86338; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Skull Valley, AZ

Summer high90 °Faverage high, July
Winter low24 °Faverage low, January
Hot days44days a year at 90 °F or more
Freezing nights128nights a year at 32 °F or less
Growing degree days3,424base 50 °F — the season’s usable heat
Longest day14 h 28 mindaylight on June 21
Shortest day9 h 50 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation16.3 inper year, rain and melted snow

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 53 °F, low 24 °F 53°24° JanFebruary: average high 55 °F, low 26 °F 55°26° FebMarch: average high 61 °F, low 32 °F 61°32° MarApril: average high 68 °F, low 37 °F 68°37° AprMay: average high 76 °F, low 45 °F 76°45° MayJune: average high 87 °F, low 54 °F 87°54° JunJuly: average high 90 °F, low 61 °F 90°61° JulAugust: average high 87 °F, low 60 °F 87°60° AugSeptember: average high 82 °F, low 52 °F 82°52° SepOctober: average high 73 °F, low 40 °F 73°40° OctNovember: average high 62 °F, low 30 °F 62°30° NovDecember: average high 52 °F, low 24 °F 52°24° Dec

Precipitation by month inches

0″1″2″3″January: 1.87 in precipitation 1.9 JanFebruary: 1.83 in precipitation 1.8 FebMarch: 1.83 in precipitation 1.8 MarApril: 0.50 in precipitation 0.5 AprMay: 0.45 in precipitation 0.5 MayJune: 0.22 in precipitation 0.2 JunJuly: 2.43 in precipitation 2.4 JulAugust: 2.38 in precipitation 2.4 AugSeptember: 1.52 in precipitation 1.5 SepOctober: 0.98 in precipitation 1.0 OctNovember: 0.91 in precipitation 0.9 NovDecember: 1.40 in precipitation 1.4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Prescott, AZ (19 mi away); precipitation: Prescott 11.1 Sw, AZ (13 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

863057b
Prescott, AZ · 14 mi
863027b
Prescott, AZ · 15 mi
863047b
Prescott, AZ · 15 mi
863137b
Prescott, AZ · 17 mi
863219a
Bagdad, AZ · 19 mi
863037b
Prescott, AZ · 19 mi
863017b
Prescott, AZ · 19 mi
863328b
Kirkland, AZ · 20 mi

Arizona planting zones →

Questions about 86338

What planting zone is ZIP code 86338?

ZIP code 86338 (Skull Valley, AZ) is in USDA hardiness zone 8a on the 2023 map: the coldest night of an average winter reaches 10 to 15 °F (−12.2 to −9.4 °C).

When is the last frost in Skull Valley, AZ?

The median last spring frost (32 °F) near 86338 is April 30; after May 15 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Prescott station.

When is the first frost in Skull Valley, AZ?

The median first fall frost near 86338 is October 20, giving a median frost-free growing season of 172 days.

When should I plant tomatoes in 86338?

Start tomato seeds indoors around Mar 5 – Mar 19 and set transplants outside around May 7 – May 21, one to three weeks after the median last frost.

How much rain and snow does 86338 get?

About 16.3 inches of precipitation a year (NOAA 1991–2020 normals, Prescott 11.1 Sw station).

How hot do summers get in Skull Valley, AZ?

The average high peaks at 90 °F in July, with about 44 days a year at 90 °F or more.

What kind of soil does 86338 have?

The USDA soil survey maps Barkerville at the center of ZIP 86338: cobbly sandy loam, well drained, pH about 7.0 (neutral).

Did spring come early in Skull Valley, AZ in 2026?

Spring leaf-out near 86338 came on Feb 3 in 2026, 15 days earlier than the 1991–2020 average (Feb 18), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Skull Valley, AZ?

Intermediate onions: the longest day near 86338 is 14 h 28 min, so day-neutral types bulb best; long-day varieties may not bulb fully.