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

Planting zone for 86547 — Round Rock, AZ

ZIP code 86547 (Round Rock, Apache County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is May 3 and the first fall frost October 17.

Where ZIP 86547 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.

Zone7a0 to 5 °F

Coldest night−17.8 to −15 °C

Last frostMay 3

First frostOct 17

2012 zone7a

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 7a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Round Rock, 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 Round Rock, AZ

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostMay 3median — 50% chance of a later frost

Safe for tender plantsMay 22only 10% chance of frost after

First fall frostOctober 17median — 10% chance by Oct 2

Growing season163 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 23 and returns around October 27.

From the NOAA station Lukachukai, AZ — 16 miles away, elevation 6,519 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 86547

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 22 – Apr 5

SpinachSow outdoors · Mar 22 – Apr 12

Broccoli, cabbageStart indoors · Feb 22 – Mar 8

Broccoli, cabbageTransplant · Apr 12 – Apr 26

Onion setsPlant outdoors · Apr 5 – Apr 19

PotatoesPlant outdoors · Apr 12 – Apr 26

LettuceSow outdoors · Apr 5 – Apr 19

Carrots, beetsSow outdoors · Apr 12 – Apr 26

TomatoesStart indoors · Mar 8 – Mar 22

TomatoesTransplant · May 10 – May 24

Peppers, eggplantStart indoors · Feb 22 – Mar 8

Peppers, eggplantTransplant · May 17 – May 31

BeansSow outdoors · May 10 – May 24

Sweet cornSow outdoors · May 10 – May 24

Cucumbers, squashSow outdoors · May 10 – May 24

Fall lettuce, spinachSow outdoors · Aug 22 – Sep 5

GarlicPlant cloves · Oct 3 – Nov 7

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 3) and first fall frost (Oct 17) 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 86547 came on Mar 2 — 16 days earlier than the 1991–2020 average (Mar 18).

average
Mar 182026
Mar 2

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 7a in Arizona

457 plants native to the lower 48 states, recorded in Arizona, and rated by the USDA to survive 0 °F or colder — the bottom of zone 7a. 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 Round Rock, AZ.

Soil in Round Rock, AZ

The soil mapped at the center of ZIP 86547 is Nakai — loamy very fine sand, somewhat excessively drained.

TextureLoamy very fine sanddrains and warms fast; dries out and needs more feeding

pH8.4alkaline; most vegetables like 6.0–7.0

DrainageSomewhat excessively drainednatural drainage class

Organic matter0.3%low — add compost

Hydrologic groupCwater soaks in slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Nakai-Somorent family complex, 1 to 15 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 86547; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Round Rock, AZ

Summer high88 °Faverage high, July

Winter low18 °Faverage low, January

Hot days22days a year at 90 °F or more

Freezing nights146nights a year at 32 °F or less

Growing degree days2,881base 50 °F — the season’s usable heat

Longest day14 h 40 mindaylight on June 21

Shortest day9 h 40 mindaylight on December 21

Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully

Precipitation26 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: Lukachukai, AZ (16 mi away); precipitation: Beaver Spring, AZ (27 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 7a.

865457a

Rock Point, AZ · 12 mi

865387a

Many Farms, AZ · 13 mi

865077a

Lukachukai, AZ · 14 mi

865447a

Red Valley, AZ · 18 mi

865037a

Chinle, AZ · 26 mi

865147a

Teec Nos Pos, AZ · 26 mi

865567a

Tsaile, AZ · 26 mi

865357a

Dennehotso, AZ · 29 mi

Arizona planting zones →

Questions about 86547

What planting zone is ZIP code 86547?

ZIP code 86547 (Round Rock, AZ) is in USDA hardiness zone 7a on the 2023 map: the coldest night of an average winter reaches 0 to 5 °F (−17.8 to −15 °C).

When is the last frost in Round Rock, AZ?

The median last spring frost (32 °F) near 86547 is May 3; after May 22 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Lukachukai station.

When is the first frost in Round Rock, AZ?

The median first fall frost near 86547 is October 17, giving a median frost-free growing season of 163 days.

When should I plant tomatoes in 86547?

Start tomato seeds indoors around Mar 8 – Mar 22 and set transplants outside around May 10 – May 24, one to three weeks after the median last frost.

How much rain and snow does 86547 get?

About 26 inches of precipitation a year (NOAA 1991–2020 normals, Beaver Spring station).

How hot do summers get in Round Rock, AZ?

The average high peaks at 88 °F in July, with about 22 days a year at 90 °F or more.

What kind of soil does 86547 have?

The USDA soil survey maps Nakai at the center of ZIP 86547: loamy very fine sand, somewhat excessively drained, pH about 8.4 (alkaline).

Did spring come early in Round Rock, AZ in 2026?

Spring leaf-out near 86547 came on Mar 2 in 2026, 16 days earlier than the 1991–2020 average (Mar 18), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Round Rock, AZ?

Intermediate onions: the longest day near 86547 is 14 h 40 min, so day-neutral types bulb best; long-day varieties may not bulb fully.