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

Planting zone for 86042 — Polacca, AZ

ZIP code 86042 (Polacca, Navajo County) is in USDA zone 7a: the coldest winter night averages 0 to 5 °F. The median last spring frost is May 16 and the first fall frost October 10.

Where ZIP 86042 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 16
First frostOct 10
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 Polacca, 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 Polacca, AZ

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 16median — 50% chance of a later frost
Safe for tender plantsJune 5only 10% chance of frost after
First fall frostOctober 10median — 10% chance by Sep 29
Growing season147 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 1 and returns around October 20.

From the NOAA station Keams Canyon, AZ — 11 miles away, elevation 6,204 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 86042

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 4 – Apr 18
SpinachSow outdoors · Apr 4 – Apr 25
Broccoli, cabbageStart indoors · Mar 7 – Mar 21
Broccoli, cabbageTransplant · Apr 25 – May 9
Onion setsPlant outdoors · Apr 18 – May 2
PotatoesPlant outdoors · Apr 25 – May 9
LettuceSow outdoors · Apr 18 – May 2
Carrots, beetsSow outdoors · Apr 25 – May 9
TomatoesStart indoors · Mar 21 – Apr 4
TomatoesTransplant · May 23 – Jun 6
Peppers, eggplantStart indoors · Mar 7 – Mar 21
Peppers, eggplantTransplant · May 30 – Jun 13
BeansSow outdoors · May 23 – Jun 6
Sweet cornSow outdoors · May 23 – Jun 6
Cucumbers, squashSow outdoors · May 23 – Jun 6
Fall lettuce, spinachSow outdoors · Aug 15 – Aug 29
GarlicPlant cloves · Sep 26 – Oct 31
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 16) and first fall frost (Oct 10) 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 86042 came on Mar 1 — 17 days earlier than the 1991–2020 average (Mar 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 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.

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 95

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 190

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 140

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 Polacca, AZ.

Soil in Polacca, AZ

The soil mapped at the center of ZIP 86042 is Torriorthents, well drained.

DrainageWell drainednatural drainage class
Farmland classNot prime farmlandUSDA classification

Map unit: Rock outcrop-Torriorthents complex, 5 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 86042; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Polacca, AZ

Summer high89 °Faverage high, July
Winter low17 °Faverage low, December
Hot days31days a year at 90 °F or more
Freezing nights172nights a year at 32 °F or less
Growing degree days2,647base 50 °F — the season’s usable heat
Longest day14 h 36 mindaylight on June 21
Shortest day9 h 43 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation8.8 inper year, rain and melted snow
Snowfall5 inper year; 1 days with snow on the ground

Average high and low, by month

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 45 °F, low 18 °F 45°18° JanFebruary: average high 49 °F, low 22 °F 49°22° FebMarch: average high 58 °F, low 27 °F 58°27° MarApril: average high 66 °F, low 32 °F 66°32° AprMay: average high 75 °F, low 39 °F 75°39° MayJune: average high 86 °F, low 47 °F 86°47° JunJuly: average high 89 °F, low 57 °F 89°57° JulAugust: average high 86 °F, low 55 °F 86°55° AugSeptember: average high 79 °F, low 47 °F 79°47° SepOctober: average high 68 °F, low 35 °F 68°35° OctNovember: average high 56 °F, low 25 °F 56°25° NovDecember: average high 44 °F, low 17 °F 44°17° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″January: 0.76 in precipitation, 1.1 in snowfall 0.8❄1 JanFebruary: 0.73 in precipitation, 0.9 in snowfall 0.7❄1 FebMarch: 0.65 in precipitation, 0.6 in snowfall 0.7❄1 MarApril: 0.48 in precipitation, 0.1 in snowfall 0.5 AprMay: 0.51 in precipitation 0.5 MayJune: 0.27 in precipitation 0.3 JunJuly: 1.07 in precipitation 1.1 JulAugust: 1.30 in precipitation 1.3 AugSeptember: 0.85 in precipitation 0.8 SepOctober: 0.83 in precipitation, 0.1 in snowfall 0.8 OctNovember: 0.58 in precipitation, 0.6 in snowfall 0.6❄1 NovDecember: 0.72 in precipitation, 1.5 in snowfall 0.7❄2 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Keams Canyon, AZ (11 mi away); precipitation: Canyon De Chelly, AZ (52 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

860437a
Second Mesa, AZ · 9 mi
860397a
Kykotsmovi Village, AZ · 13 mi
860346b
Keams Canyon, AZ · 15 mi
860307a
Hotevilla, AZ · 23 mi
865106b
Pinon, AZ · 26 mi
865207a
Blue Gap, AZ · 26 mi
860317a
Indian Wells, AZ · 39 mi
865056b
Ganado, AZ · 41 mi

Arizona planting zones →

Questions about 86042

What planting zone is ZIP code 86042?

ZIP code 86042 (Polacca, 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 Polacca, AZ?

The median last spring frost (32 °F) near 86042 is May 16; after June 5 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Keams Canyon station.

When is the first frost in Polacca, AZ?

The median first fall frost near 86042 is October 10, giving a median frost-free growing season of 147 days.

When should I plant tomatoes in 86042?

Start tomato seeds indoors around Mar 21 – Apr 4 and set transplants outside around May 23 – Jun 6, one to three weeks after the median last frost.

How much rain and snow does 86042 get?

About 8.8 inches of precipitation a year and 5 inches of snowfall (NOAA 1991–2020 normals, Canyon De Chelly station).

How hot do summers get in Polacca, AZ?

The average high peaks at 89 °F in July, with about 31 days a year at 90 °F or more.

Did spring come early in Polacca, AZ in 2026?

Spring leaf-out near 86042 came on Mar 1 in 2026, 17 days earlier than the 1991–2020 average (Mar 18), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Polacca, AZ?

Intermediate onions: the longest day near 86042 is 14 h 36 min, so day-neutral types bulb best; long-day varieties may not bulb fully.