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

Planting zone for 86515 — Window Rock, AZ

ZIP code 86515 (Window Rock, Apache County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is May 29 and the first fall frost September 28.

Where ZIP 86515 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.

Zone6b−5 to 0 °F
Coldest night−20.6 to −17.8 °C
Last frostMay 29
First frostSep 28
2012 zone6a

Was 6a on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 6b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Window 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 Window Rock, AZ

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 29median — 50% chance of a later frost
Safe for tender plantsJune 10only 10% chance of frost after
First fall frostSeptember 28median — 10% chance by Sep 16
Growing season121 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 13 and returns around October 4.

From the NOAA station Window Rock Airport, AZ — 6 miles away, elevation 6,739 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 86515

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 17 – May 1
SpinachSow outdoors · Apr 17 – May 8
Broccoli, cabbageStart indoors · Mar 20 – Apr 3
Broccoli, cabbageTransplant · May 8 – May 22
Onion setsPlant outdoors · May 1 – May 15
PotatoesPlant outdoors · May 8 – May 22
LettuceSow outdoors · May 1 – May 15
Carrots, beetsSow outdoors · May 8 – May 22
TomatoesStart indoors · Apr 3 – Apr 17
TomatoesTransplant · Jun 5 – Jun 19
Peppers, eggplantStart indoors · Mar 20 – Apr 3
Peppers, eggplantTransplant · Jun 12 – Jun 26
BeansSow outdoors · Jun 5 – Jun 19
Sweet cornSow outdoors · Jun 5 – Jun 19
Cucumbers, squashSow outdoors · Jun 5 – Jun 19
Fall lettuce, spinachSow outdoors · Aug 3 – Aug 17
GarlicPlant cloves · Sep 14 – Oct 19
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 29) and first fall frost (Sep 28) 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 86515 came on Mar 19 — 15 days earlier than the 1991–2020 average (Apr 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).

Native plants for zone 6b in Arizona

441 plants native to the lower 48 states, recorded in Arizona, and rated by the USDA to survive −5 °F or colder — the bottom of zone 6b. Each links to its USDA PLANTS profile.

Trees 23

Arizona cypress50 ft · blooms spring · low shade tolerance · to −23 °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 °Fboxelder60 ft · blooms early spring · low shade tolerance · to −46 °F

Shrubs 87

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 187

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 137

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 Window Rock, AZ.

Soil in Window Rock, AZ

The soil mapped at the center of ZIP 86515 is Querencia — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH8.1alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Querencia and Gish soils, 0 to 2 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 86515; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Window Rock, AZ

Summer high88 °Faverage high, July
Winter low14 °Faverage low, January
Hot days24days a year at 90 °F or more
Freezing nights196nights a year at 32 °F or less
Growing degree days2,321base 50 °F — the season’s usable heat
Longest day14 h 35 mindaylight on June 21
Shortest day9 h 44 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation11.3 inper year, rain and melted snow

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 45 °F, low 14 °F 45°14° JanFebruary: average high 49 °F, low 19 °F 49°19° FebMarch: average high 58 °F, low 24 °F 58°24° MarApril: average high 65 °F, low 29 °F 65°29° AprMay: average high 74 °F, low 36 °F 74°36° MayJune: average high 85 °F, low 45 °F 85°45° JunJuly: average high 88 °F, low 55 °F 88°55° JulAugust: average high 85 °F, low 52 °F 85°52° AugSeptember: average high 79 °F, low 43 °F 79°43° SepOctober: average high 68 °F, low 31 °F 68°31° OctNovember: average high 56 °F, low 21 °F 56°21° NovDecember: average high 46 °F, low 14 °F 46°14° Dec

Precipitation by month inches

0″1″2″January: 1.04 in precipitation 1.0 JanFebruary: 0.87 in precipitation 0.9 FebMarch: 0.66 in precipitation 0.7 MarApril: 0.46 in precipitation 0.5 AprMay: 0.57 in precipitation 0.6 MayJune: 0.28 in precipitation 0.3 JunJuly: 1.78 in precipitation 1.8 JulAugust: 1.85 in precipitation 1.9 AugSeptember: 1.34 in precipitation 1.3 SepOctober: 0.92 in precipitation 0.9 OctNovember: 0.75 in precipitation 0.8 NovDecember: 0.83 in precipitation 0.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Window Rock Airport, AZ (6 mi away); precipitation: Window Rock Airport, AZ (6 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.

873206b
Mexican Springs, NM · 9 mi
873756b
Yatahey, NM · 11 mi
865046b
Fort Defiance, AZ · 14 mi
873176b
Gamerco, NM · 16 mi
873196a
Mentmore, NM · 16 mi
873016a
Gallup, NM · 18 mi
873026a
Gallup, NM · 18 mi
873106b
Brimhall, NM · 22 mi

Arizona planting zones →

Questions about 86515

What planting zone is ZIP code 86515?

ZIP code 86515 (Window Rock, AZ) is in USDA hardiness zone 6b on the 2023 map: the coldest night of an average winter reaches −5 to 0 °F (−20.6 to −17.8 °C).

When is the last frost in Window Rock, AZ?

The median last spring frost (32 °F) near 86515 is May 29; after June 10 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Window Rock Airport station.

When is the first frost in Window Rock, AZ?

The median first fall frost near 86515 is September 28, giving a median frost-free growing season of 121 days.

When should I plant tomatoes in 86515?

Start tomato seeds indoors around Apr 3 – Apr 17 and set transplants outside around Jun 5 – Jun 19, one to three weeks after the median last frost.

How much rain and snow does 86515 get?

About 11.3 inches of precipitation a year (NOAA 1991–2020 normals, Window Rock Airport station).

How hot do summers get in Window Rock, AZ?

The average high peaks at 88 °F in July, with about 24 days a year at 90 °F or more.

What kind of soil does 86515 have?

The USDA soil survey maps Querencia at the center of ZIP 86515: silt loam, well drained, pH about 8.1 (alkaline).

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

Spring leaf-out near 86515 came on Mar 19 in 2026, 15 days earlier than the 1991–2020 average (Apr 3), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Window Rock, AZ?

Intermediate onions: the longest day near 86515 is 14 h 35 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 86515 change?

Yes. The 2012 USDA map put 86515 in zone 6a; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.