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

Planting zone for 86511 — Saint Michaels, AZ

ZIP code 86511 (Saint Michaels, Apache County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is May 15 and the first fall frost October 10.

Where ZIP 86511 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.

Zone6a−10 to −5 °F
Coldest night−23.3 to −20.6 °C
Last frostMay 15
First frostOct 10
2012 zone6a

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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Saint Michaels, 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 Saint Michaels, AZ

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 15median — 50% chance of a later frost
Safe for tender plantsJune 1only 10% chance of frost after
First fall frostOctober 10median — 10% chance by Sep 28
Growing season147 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 2 and returns around October 19.

From the NOAA station Ganado, AZ — 11 miles away, elevation 6,339 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 86511

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 3 – Apr 17
SpinachSow outdoors · Apr 3 – Apr 24
Broccoli, cabbageStart indoors · Mar 6 – Mar 20
Broccoli, cabbageTransplant · Apr 24 – May 8
Onion setsPlant outdoors · Apr 17 – May 1
PotatoesPlant outdoors · Apr 24 – May 8
LettuceSow outdoors · Apr 17 – May 1
Carrots, beetsSow outdoors · Apr 24 – May 8
TomatoesStart indoors · Mar 20 – Apr 3
TomatoesTransplant · May 22 – Jun 5
Peppers, eggplantStart indoors · Mar 6 – Mar 20
Peppers, eggplantTransplant · May 29 – Jun 12
BeansSow outdoors · May 22 – Jun 5
Sweet cornSow outdoors · May 22 – Jun 5
Cucumbers, squashSow outdoors · May 22 – Jun 5
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 15) 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 86511 came on Mar 18 — 12 days earlier than the 1991–2020 average (Mar 30).

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 6a in Arizona

436 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 6a. Each links to its USDA PLANTS profile.

Trees 22

Arizona cypress50 ft · blooms spring · low shade tolerance · to −23 °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 °Fbristlecone pine40 ft · blooms mid summer · high shade tolerance · to −33 °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 185

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 135

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 Saint Michaels, AZ.

Soil in Saint Michaels, AZ

The soil mapped at the center of ZIP 86511 is Plumasano — loamy sand, well drained.

TextureLoamy sanddrains and warms fast; dries out and needs more feeding
pH8.0alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.25%low — add compost
Hydrologic groupAwater soaks in fast
Farmland classNot prime farmlandUSDA classification

Map unit: Plumasano-Parkelei 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 86511; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Saint Michaels, AZ

Summer high89 °Faverage high, July
Winter low18 °Faverage low, January
Hot days34days a year at 90 °F or more
Freezing nights174nights a year at 32 °F or less
Growing degree days2,719base 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

10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 44 °F, low 18 °F 44°18° JanFebruary: average high 49 °F, low 20 °F 49°20° FebMarch: average high 58 °F, low 27 °F 58°27° MarApril: average high 65 °F, low 31 °F 65°31° AprMay: average high 74 °F, low 40 °F 74°40° MayJune: average high 85 °F, low 49 °F 85°49° JunJuly: average high 89 °F, low 56 °F 89°56° JulAugust: average high 87 °F, low 56 °F 87°56° AugSeptember: average high 80 °F, low 48 °F 80°48° SepOctober: average high 69 °F, low 35 °F 69°35° OctNovember: average high 55 °F, low 25 °F 55°25° NovDecember: average high 45 °F, low 18 °F 45°18° 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: Ganado, AZ (11 mi away); precipitation: Window Rock Airport, AZ (18 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.

865406b
Nazlini, AZ · 15 mi
865046b
Fort Defiance, AZ · 15 mi
865056b
Ganado, AZ · 21 mi
865156b
Window Rock, AZ · 22 mi
865066b
Houck, AZ · 27 mi
873286b
Navajo, NM · 28 mi
873206b
Mexican Springs, NM · 28 mi
873196a
Mentmore, NM · 30 mi

Arizona planting zones →

Questions about 86511

What planting zone is ZIP code 86511?

ZIP code 86511 (Saint Michaels, AZ) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Saint Michaels, AZ?

The median last spring frost (32 °F) near 86511 is May 15; after June 1 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Ganado station.

When is the first frost in Saint Michaels, AZ?

The median first fall frost near 86511 is October 10, giving a median frost-free growing season of 147 days.

When should I plant tomatoes in 86511?

Start tomato seeds indoors around Mar 20 – Apr 3 and set transplants outside around May 22 – Jun 5, one to three weeks after the median last frost.

How much rain and snow does 86511 get?

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

How hot do summers get in Saint Michaels, AZ?

The average high peaks at 89 °F in July, with about 34 days a year at 90 °F or more.

What kind of soil does 86511 have?

The USDA soil survey maps Plumasano at the center of ZIP 86511: loamy sand, well drained, pH about 8.0 (alkaline).

Did spring come early in Saint Michaels, AZ in 2026?

Spring leaf-out near 86511 came on Mar 18 in 2026, 12 days earlier than the 1991–2020 average (Mar 30), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Saint Michaels, AZ?

Intermediate onions: the longest day near 86511 is 14 h 35 min, so day-neutral types bulb best; long-day varieties may not bulb fully.