December 4, 2025
Palo Alto City Council
250 Hamilton Ave
Palo Alto, CA 94301
Re: December 8 Agenda Item 15 - Dark Sky (Outdoor Lighting) Ordinance
Dear Mayor Lauing and Palo Alto City Councilmembers,
The Santa Clara Valley Bird Alliance and the Sierra Club Loma Prieta Chapter support the adoption of Palo Alto’s Dark Sky (Outdoor Lighting) Ordinance, and suggest a few critical corrections. We appreciate the extensive work by City staff, and the clear direction from the Planning and Transportation Commission and Council to develop a measure that protects migratory birds, nocturnal wildlife, and human health while conserving energy and restoring the City’s night sky.
The ordinance follows best practices from DarkSky International and the Illuminating Engineering Society by ensuring that lighting is shielded, directed, and used only where and when needed. Please consider incorporating the following five requests. We have made changes in blue since our November 10th letter to the City Council on this subject.
Amend Sections 18.40.250(d)(4) and 18.40.250(e)(4)(A) to adjust the curfew start time from 12 a.m. to 11 p.m.
Amend Section 18.40.250(c)(3) to remove the phrase “If a building permit is required” to apply the ordinance to all new installation, replacement, or modification of outdoor luminaires,
Amend Section 18.40.250(d)(7) to ensure that prohibited lighting types are not allowed in the exempted Edgewood Drive properties,
Remove 18.40.250(L)(2)(A)(B) and (3), removing retrofit requirements for existing outdoor lighting, and
Retain and shorten the compliance period in Section 18.40.250(L)(1) for easily adjustable existing lighting fixtures to one year.
Request #1
Amend Sections 18.40.250(d)(4) and 18.40.250(e)(4)(A) to adjust the curfew start time from 12 a.m. to 11 p.m
Current text
Section 18.40.250(d) Exemptions. The following types of lighting are exempt from the lighting requirements of the section:
(4) Seasonal lighting, subject to extinguishment at 12:00 a.m., during the period of October 15 through January 15 of each year;
Section 18.40.250(e) Lighting Standards.
(4) Lighting Control.
(A) Lighting Curfew. Unlike other provisions in this section, the Lighting Curfew shall apply to all outdoor luminaires for new and existing buildings and structures, unless otherwise approved. All outdoor lighting shall be fully extinguished or be motion sensor operated by 12:00 a.m., two hours after the close of business, or when people are no longer present in exterior areas, whichever is later.
Proposed Text
Section 18.40.250(d) Exemptions. The following types of lighting are exempt from the lighting requirements of the section:
(4) Seasonal lighting, subject to extinguishment at 11:00 p.m. 12:00 a.m., during the period of October 15 through January 15 of each year;
Section 18.40.250(e) Lighting Standards.
(4) Lighting Control.
(A) Lighting Curfew. Unlike other provisions in this section, the Lighting Curfew shall apply to all outdoor luminaires for new and existing buildings and structures, unless otherwise approved. All outdoor lighting shall be fully extinguished or be motion sensor operated by 11:00 p.m. 12:00 a.m., two hours after the close of business, or when people are no longer present in exterior areas, whichever is later.
Justification
The Lighting Curfew standards in this ordinance are incredibly flexible, allowing for lights to remain on two hours after the close of business or when people are no longer present in exterior areas, whichever is later. Adjusting the start time of the curfew will not affect luminaires that remain illuminated at late hours for those reasons. Adjusting the curfew start time one hour earlier, to 11:00 p.m. will allow the ordinance to maximize its light pollution reduction at key nighttime hours while retaining the flexibility to allow residents and businesses to operate normally.
Furthermore, the 11:00 p.m. time would correspond with the curfews of many other adopted ordinances, such as those in Cupertino, Malibu, and Los Altos, which all use 11pm residential curfews. Brisbane and Rancho Palos Verdes contain curfews which, at the latest, begin at 10 p.m.
Request #2
Amend Section 18.40.250(c)(3) to remove the phrase “If a building permit is required” to apply the ordinance to all new installation, replacement, or modification of outdoor luminaires.
Current text
(3) If a building permit is required: New installation of outdoor luminaires, replacement of existing outdoor luminaires, or modifications to the lighting type or system.
Proposed Text
(3) If a building permit is required: New installation of outdoor luminaires, replacement of existing outdoor luminaires, or modifications to the lighting type or system.
Justification
Both the Planning and Transportation Commission (October 30, 2024) and the City Council (April 7, 2025) explicitly directed that the lighting standards apply to all new and replacement outdoor lighting. The April 7th City Council minutes1 and the staff report for Item 8 confirm this directive, yet the draft ordinance retains the inconsistent “building permit” qualifier.
Limiting applicability to projects requiring a building permit creates a major loophole that exempts most fixture replacements and new lighting installations. Since lighting installations do not typically require permits, much new and replacement lighting would remain unregulated. Removing the “building permit” qualifier will bring the ordinance into alignment with Council direction and ensure it functions as intended.
Request #3
Amend Section 18.40.250(d)(7) to ensure that prohibited lighting types are not allowed in the exempted Edgewood Drive properties.
Current Text
“(7) Single family residential sites adjacent to San Francisquito Creek and fronting on Edgewood Drive if the portion of the site subject to a permanent easement in favor of the Santa Clara Valley Water District (or its successor in interest) for flood control purposes is reconfigured after January 1, 2002. These sites shall be subject to the requirements under Section 18.40.250(e)(4)(A).”
Proposed Text
(7) Single family residential sites adjacent to San Francisquito Creek and fronting on Edgewood Drive if the portion of the site subject to a permanent easement in favor of the Santa Clara Valley Water District (or its successor in interest) for flood control purposes is reconfigured after January 1, 2002. These sites shall be subject to the requirements under Sections 18.40.250(e)(4)(A) and 18.40.250(g).
Justification
While we appreciate that Section 18.40.250(e)(4)(A) applies the lighting curfew, the exemption in (d)(7) inadvertently allows the use of prohibited lighting such as blinking, flashing, or rotating lights, and searchlights, aerial lasers, or spotlights, all forms of illumination that are unnecessary for safety and highly disruptive to wildlife. Safety can be achieved using fully shielded, dark-sky-compliant luminaires. Extending the prohibited lighting clause to this area will prevent excessive glare and protect one of Palo Alto’s most sensitive riparian corridors along San Francisquito Creek.
Request #4
Remove 18.40.250(L)(2)(A)(B) and (3), removing retrofit requirements for existing outdoor lighting
Current Text (Section 18.40.250(L)
“(L) Existing Nonconforming Lighting
(1) Within two years of [the effective date of this ordinance]: Where existing outdoor luminaires have the ability to adjust (through existing dimmers, directional adjustability, timers, etc.), the requirements under Section 18.40.140(e), except for the shielding requirements under subsection 18.40.140(e)(1), shall apply.
(2) For all existing outdoor luminaires, the requirements under Section 18.40.140(e) shall apply within the following timeframes from [the effective date of this ordinance]:
(A) Residential and Mixed Use Zoning Districts: Within ten years.
(B) Nonresidential Zoning Districts: Within five years.
(3) Any nonconforming lighting still in place after the compliance deadline shall remain extinguished at all times until they are brought into compliance.
Proposed Revision
Keep (L)(1) to retain the requirement that all easily-adjustable luminaires be adjusted to be compliant with the ordinance. We recommend adjusting the timing window of (l)(1), as described below in Request #4.
Delete subsections (L)(2)(A) and (B) and (3), removing the retrofit schedule.
(2) For all existing outdoor luminaires, the requirements under Section 18.40.140(e) shall apply within the following timeframes from [the effective date of this ordinance]:
(A) Residential and Mixed Use Zoning Districts: Within ten years.
(B) Nonresidential Zoning Districts: Within five years.
(3) Any nonconforming lighting still in place after the compliance deadline shall remain extinguished at all times until they are brought into compliance.
Justification
Requiring retrofits for all existing lighting could be difficult to administer and monitor, and can create hardship for residents and businesses. Applying the ordinance to all new, replacement, and easily-modified lighting would achieve gradual citywide compliance through equipment turnover while avoiding confusion and unnecessary administrative burden.
Retaining the hardship exemption (Section 18.40.250(j)) and clear applicability to all new and replacement lighting ensures that future installations meet dark-sky standards without imposing mandatory retrofits on existing luminaires.
Request #5
Retain and shorten the compliance period in Section 18.40.250(L)(1) for easily adjustable existing lighting fixtures to one year
Current Text (Section 18.40.250(L)(1))
“(1) Within two years of [the effective date of this ordinance]: Where existing outdoor luminaires have the ability to adjust (through existing dimmers, directional adjustability, timers, etc.), the requirements under Section 18.40.140(e), except for the shielding requirements under subsection 18.40.140(e)(1), shall apply.”
Proposed Text
“(1) Within one year two years of [the effective date of this ordinance]: Where existing outdoor luminaires have the ability to adjust (through existing dimmers, directional adjustability, timers, etc.), the requirements under Section 18.40.140(e), except for the shielding requirements under subsection 18.40.140(e)(1), shall apply.”
Justification
A two-year grace period is unnecessarily long for fixtures that can be corrected through simple adjustments such as dimming, re-aiming, or resetting timers. Comparable Dark Sky ordinances, including Brisbane’s, require compliance within one year. A one year window provides sufficient time for the City to distribute educational materials and for property owners to make straightforward adjustments, achieving measurable reductions in light pollution much sooner.
In Conclusion
With the brief but critically important modifications we have suggested, Palo Alto’s dark sky ordinance will reduce light pollution over time and improve public health and public safety and protect migratory birds and wildlife. The provisions of this ordinance are in line with successfully adopted dark sky ordinances throughout the nation. The requirements are extremely flexible, ensuring that business in Palo Alto will not be impeded, and are robust enough to protect residents and wildlife from the dangers of over-lighting. Please move to adopt this ordinance, with the modifications we have suggested.
Sincerely,
Shani Kleinhaus
Environmental Advocate
Santa Clara Valley Bird Alliance
Dashiell Leeds
Conservation Coordinator
Sierra Club Loma Prieta Chapter