Temecula, CA Outdoor Lighting: Dark Sky Rules (2026)

Riverside County Ordinance 655 (the Mt. Palomar Light Pollution Control Ordinance) applies to all of Temecula because the city sits within Zone B (15-45 mile radius from Mt. Palomar Observatory). The ordinance protects the observatory's ability to conduct astronomical research by limiting artificial sky glow. Requirements for new outdoor lighting in Zone B include: all fixtures over 4,000 lumens (roughly equivalent to a 250W incandescent) must be fully shielded so the bulb is not visible from the side and no light is emitted above the horizontal plane. Low-pressure sodium (LPS) lighting is preferred for street and parking lot lighting; filtered LED is acceptable when LPS is impractical. LED color temperature should be 3000K or warmer (no harsh blue-white above 4100K). Decorative residential string lights, holiday displays, and low-wattage path lights receive lighter regulation. Commercial outdoor lighting (parking lots, building floods, signs) must comply with maximum lumen-per-acre limits and curfew provisions (lights reduced or off between 11 PM and sunrise where practical). New construction projects must submit lighting plans with photometric calculations as part of building permit review. Existing nonconforming lighting is grandfathered until replacement, at which point new fixtures must comply. The City coordinates with RivCo Code Enforcement and the observatory's outreach program. Violations can be reported via the Code Enforcement complaint system.