Flagstaff, AZ Outdoor Lighting: Dark Sky Rules (2026)

Flagstaff earned recognition as the world's first International Dark Sky City on October 24, 2001, and Section 10-50.70.010 states the purpose of its outdoor lighting division: preserving the dark sky resource that its astronomical industry depends on, minimizing light pollution and light trespass across property lines, reducing energy use, and protecting nocturnal ecosystems, while still allowing safe outdoor lighting. The City is split into two lighting zones under Section 10-50.70.040, based on distance from the Kaj Strand telescope at the U.S. Naval Observatory: Lighting Zone 1 covers everything within two and one-half miles of the telescope and carries the tighter limits, while Lighting Zone 2 covers everything beyond that distance.

Every fixture is classified by function into Class 1 (color-critical lighting such as sales areas and outdoor eating areas, capped at 2,700 Kelvin), Class 2 (safety and security lighting, which must use narrow-spectrum amber LEDs), or Class 3 (decorative lighting). Table 10-50.70.050.C then dictates shielding by class, land use, and zone, and Section 10-50.70.050.D requires that any fixture the table marks as fully shielded actually satisfy the code's definition of a Fully Shielded Light Fixture, not merely a partial baffle. The division sets numeric ceilings on total light output per acre or per lot in Table 10-50.70.050.B, and Section 10-50.70.050.N bans mercury vapor fixtures outright anywhere in the City, except systems already erected before 1950. Commercial and industrial lighting, apart from approved Class 2 security lighting, must go dark no later than 30 minutes after the business closes.