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

Planting zone for 86002 — Flagstaff, AZ

ZIP code 86002 (Flagstaff, Coconino County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is June 4 and the first fall frost September 28.

Where ZIP 86002 is

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 frostJun 4

First frostSep 28

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 Flagstaff, 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 Flagstaff, AZ

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostJune 4median — 50% chance of a later frost

Safe for tender plantsJune 19only 10% chance of frost after

First fall frostSeptember 28median — 10% chance by Sep 16

Growing season115 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 20 and returns around October 9.

From the NOAA station Flagstaff Pulliam Airport, AZ — 4 miles away, elevation 7,005 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 86002

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Apr 23 – May 7

SpinachSow outdoors · Apr 23 – May 14

Broccoli, cabbageStart indoors · Mar 26 – Apr 9

Broccoli, cabbageTransplant · May 14 – May 28

Onion setsPlant outdoors · May 7 – May 21

PotatoesPlant outdoors · May 14 – May 28

LettuceSow outdoors · May 7 – May 21

Carrots, beetsSow outdoors · May 14 – May 28

TomatoesStart indoors · Apr 9 – Apr 23

TomatoesTransplant · Jun 11 – Jun 25

Peppers, eggplantStart indoors · Mar 26 – Apr 9

Peppers, eggplantTransplant · Jun 18 – Jul 2

BeansSow outdoors · Jun 11 – Jun 25

Sweet cornSow outdoors · Jun 11 – Jun 25

Cucumbers, squashSow outdoors · Jun 11 – Jun 25

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 (Jun 4) 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 86002 came on Mar 10 — 31 days earlier than the 1991–2020 average (Apr 10).

average
Apr 102026
Mar 10

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.

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 Flagstaff, AZ.

Soil in Flagstaff, AZ

The soil mapped at the center of ZIP 86002 is Lynx — loam, well drained.

TextureLoama good balance for most vegetables

pH8.0alkaline; most vegetables like 6.0–7.0

DrainageWell drainednatural drainage class

Organic matter2%moderate

Hydrologic groupBwater soaks in moderately

Farmland classNot prime farmlandUSDA classification

Map unit: Lynx loam, 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 86002; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Flagstaff, AZ

Summer high82 °Faverage high, July

Winter low17 °Faverage low, December

Hot days3days a year at 90 °F or more

Freezing nights202nights a year at 32 °F or less

Growing degree days1,723base 50 °F — the season’s usable heat

Longest day14 h 32 mindaylight on June 21

Shortest day9 h 47 mindaylight on December 21

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

Precipitation22.1 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: Flagstaff Pulliam Airport, AZ (4 mi away); precipitation: Flagstaff 2.2 Sw, AZ (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

Flagstaff, AZ · 13 mi

860177a

Munds Park, AZ · 18 mi

860186b

Parks, AZ · 18 mi

860046b

Flagstaff, AZ · 20 mi

860386b

Mormon Lake, AZ · 22 mi

863398b

Sedona, AZ · 24 mi

All 5 ZIP codes in Flagstaff → · Arizona planting zones →

Questions about 86002

What planting zone is ZIP code 86002?

ZIP code 86002 (Flagstaff, 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 Flagstaff, AZ?

The median last spring frost (32 °F) near 86002 is June 4; after June 19 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Flagstaff Pulliam Airport station.

When is the first frost in Flagstaff, AZ?

The median first fall frost near 86002 is September 28, giving a median frost-free growing season of 115 days.

When should I plant tomatoes in 86002?

Start tomato seeds indoors around Apr 9 – Apr 23 and set transplants outside around Jun 11 – Jun 25, one to three weeks after the median last frost.

How much rain and snow does 86002 get?

About 22.1 inches of precipitation a year (NOAA 1991–2020 normals, Flagstaff 2.2 Sw station).

How hot do summers get in Flagstaff, AZ?

The average high peaks at 82 °F in July, with about 3 days a year at 90 °F or more.

What kind of soil does 86002 have?

The USDA soil survey maps Lynx at the center of ZIP 86002: loam, well drained, pH about 8.0 (alkaline).

Did spring come early in Flagstaff, AZ in 2026?

Spring leaf-out near 86002 came on Mar 10 in 2026, 31 days earlier than the 1991–2020 average (Apr 10), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Flagstaff, AZ?

Intermediate onions: the longest day near 86002 is 14 h 32 min, so day-neutral types bulb best; long-day varieties may not bulb fully.