Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 86016 — Gray Mountain, AZ

ZIP code 86016 (Gray Mountain, Coconino County) is in USDA zone 6b: the coldest winter night averages −5 to 0 °F. The median last spring frost is April 7 and the first fall frost November 3.

Where ZIP 86016 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 frostApr 7

First frostNov 3

2012 zone7b

Was 7b on the 2012 map — a full zone colder 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 Gray Mountain, 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 Gray Mountain, AZ

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 7median — 50% chance of a later frost

Safe for tender plantsApril 30only 10% chance of frost after

First fall frostNovember 3median — 10% chance by Oct 19

Growing season206 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 17 and returns around November 14.

From the NOAA station Wupatki Nm, AZ — 22 miles away, elevation 4,908 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 86016

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Feb 24 – Mar 10

SpinachSow outdoors · Feb 24 – Mar 17

Broccoli, cabbageStart indoors · Jan 27 – Feb 10

Broccoli, cabbageTransplant · Mar 17 – Mar 31

Onion setsPlant outdoors · Mar 10 – Mar 24

PotatoesPlant outdoors · Mar 17 – Mar 31

LettuceSow outdoors · Mar 10 – Mar 24

Carrots, beetsSow outdoors · Mar 17 – Mar 31

TomatoesStart indoors · Feb 10 – Feb 24

TomatoesTransplant · Apr 14 – Apr 28

Peppers, eggplantStart indoors · Jan 27 – Feb 10

Peppers, eggplantTransplant · Apr 21 – May 5

BeansSow outdoors · Apr 14 – Apr 28

Sweet cornSow outdoors · Apr 14 – Apr 28

Cucumbers, squashSow outdoors · Apr 14 – Apr 28

Fall lettuce, spinachSow outdoors · Sep 8 – Sep 22

GarlicPlant cloves · Oct 20 – Nov 24

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 7) and first fall frost (Nov 3) 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 86016 came on Mar 1 — 13 days earlier than the 1991–2020 average (Mar 14).

average
Mar 142026
Mar 1

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.

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 Gray Mountain, AZ.

Soil in Gray Mountain, AZ

The soil mapped at the center of ZIP 86016 is Meriwhitica — very gravelly fine sandy loam, well drained.

TextureVery gravelly fine sandy loamdrains and warms fast; dries out and needs more feeding

pH8.2alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter0.5%low — add compost

Hydrologic groupDwater soaks in very slowly

Farmland classNot prime farmlandUSDA classification

Map unit: Meriwhitica-Wayneco-Tassi family, complex, 5 to 30 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 86016; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Gray Mountain, AZ

Summer high94 °Faverage high, July

Winter low25 °Faverage low, December

Hot days80days a year at 90 °F or more

Freezing nights94nights a year at 32 °F or less

Growing degree days4,416base 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

Precipitation8.5 inper year, rain and melted snow

Snowfall3 inper year; 3 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Wupatki Nm, AZ (22 mi away); precipitation: Wupatki Nm, AZ (22 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

860207b

Cameron, AZ · 18 mi

860016a

Flagstaff, AZ · 28 mi

860237a

Grand Canyon, AZ · 29 mi

860046b

Flagstaff, AZ · 30 mi

860467a

Williams, AZ · 37 mi

860155b

Bellemont, AZ · 38 mi

860026a

Flagstaff, AZ · 38 mi

860457b

Tuba City, AZ · 40 mi

Arizona planting zones →

Questions about 86016

What planting zone is ZIP code 86016?

ZIP code 86016 (Gray Mountain, 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 Gray Mountain, AZ?

The median last spring frost (32 °F) near 86016 is April 7; after April 30 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Wupatki Nm station.

When is the first frost in Gray Mountain, AZ?

The median first fall frost near 86016 is November 3, giving a median frost-free growing season of 206 days.

When should I plant tomatoes in 86016?

Start tomato seeds indoors around Feb 10 – Feb 24 and set transplants outside around Apr 14 – Apr 28, one to three weeks after the median last frost.

How much rain and snow does 86016 get?

About 8.5 inches of precipitation a year and 3 inches of snowfall (NOAA 1991–2020 normals, Wupatki Nm station).

How hot do summers get in Gray Mountain, AZ?

The average high peaks at 94 °F in July, with about 80 days a year at 90 °F or more.

What kind of soil does 86016 have?

The USDA soil survey maps Meriwhitica at the center of ZIP 86016: very gravelly fine sandy loam, well drained, pH about 8.2 (alkaline).

Did spring come early in Gray Mountain, AZ in 2026?

Spring leaf-out near 86016 came on Mar 1 in 2026, 13 days earlier than the 1991–2020 average (Mar 14), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Gray Mountain, AZ?

Intermediate onions: the longest day near 86016 is 14 h 35 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 86016 change?

Yes. The 2012 USDA map put 86016 in zone 7b; the 2023 map puts it in zone 6b. The newer map uses 1991–2020 data and more weather stations.