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Planting zones · Flagstaff, Arizona

What Planting Zone Is Flagstaff?

Flagstaff is in USDA zone 6a–6b. Colorado Plateau pine country at about 7,000 ft: about 20.5 in. of precipitation, 90 in. of snow, and one of the shortest frost-free seasons in the region (about 115 days, last frost around June 4).

  • USDA zone (2023)6a–6b
  • Coldest night (avg.)-10 to -5°FZIP 86001
  • Median last frostJun 432°F
  • Median first frostSep 2832°F
  • Annual precipitation21 inches
  • Frost-free season115 days

Flagstaff hardiness zone by ZIP code

On the 2023 USDA Plant Hardiness Zone Map, the ZIP codes we sampled in Flagstaff fall in zones 6a to 6b; 86001 (zone 6a) has an average annual extreme minimum of -10 to -5°F. Choose perennials, shrubs, and trees rated at least to zone 6.

2023 USDA zone for sampled Flagstaff ZIP codes
ZIPZoneAvg. coldest night
860016a-10 to -5°F
860046b-5 to 0°F

Not listed? Look up any ZIP code.

Frost dates and when to plant

The median last spring frost (32°F) at Flagstaff Pulliam Airport is Jun 4 and the median first fall frost is Sep 28, a typical frost-free season of about 115 days.

Plant container perennials and shrubs after the median last frost (Jun 4), or in early fall at least six weeks before the median first frost (Sep 28) so roots can settle in before the ground freezes.

Rainfall and heat in Flagstaff

Average annual precipitation is 21 inches (Flagstaff Pulliam Airport, 1991–2020), spread across the year with August the wettest month and June the driest.

The average high in July is about 82°F and the average low in December is about 17°F, measured at about 7,000 ft.

That is why a zone rating alone isn't enough for a xeriscape here: pick plants that are both cold-hardy to zone 6 and rated very low or low water once established.

Low-water plants for Flagstaff

72 plants in our database are hardy to zone 6 and suited to zone 6. Here are 12, driest first, across plant types.

See all zone 6 plants

Frequently asked questions

What planting zone is Flagstaff?

Flagstaff, AZ is in USDA hardiness zone 6a–6b on the 2023 USDA Plant Hardiness Zone Map, based on the ZIP codes we sampled (86001: 6a, 86004: 6b). In 86001, the average coldest night of the year is -10 to -5°F.

When is the last frost in Flagstaff?

The median last spring frost (32°F) at Flagstaff Pulliam Airport is Jun 4 and the median first fall frost is Sep 28, a typical frost-free season of about 115 days.

How much rain does Flagstaff get?

Average annual precipitation is 21 inches (Flagstaff Pulliam Airport, 1991–2020), spread across the year with August the wettest month and June the driest.

Sources

  1. NOAA NCEI U.S. Climate Normals 1991–2020, Flagstaff Pulliam Airport (USW00003103). ncei.noaa.gov
  2. USDA ARS 2023 Plant Hardiness Zone Map, by ZIP. planthardiness.ars.usda.gov