Fort Collins, CO Outdoor Lighting: Dark Sky Rules (2026)
Key Facts
- CCT cap
- 3000 Kelvin maximum
- Prohibited fixtures
- Mercury vapor lamps
- Pole finish
- Anodized or coated to cut glare
- Lighting zones
- LC0 (none) through LC3 (highest)
- Applies to
- Applications filed before May 17, 2024
Summary
New development in Fort Collins had to cap outdoor light color at 3000 Kelvin, use anodized poles to cut glare, and skip mercury vapor lamps entirely under Section 3.2.4 of the Transitional Land Use Code. The rule applied to development applications filed before May 17, 2024, so verify a project's filing date before citing it as current.
3.2.4 - Exterior Site Lighting (A)Purpose. The purpose of this Section is to ensure adequate exterior lighting for the safety, security, enjoyment and function of the proposed land use; conserve energy and resources; reduce light trespass, glare, artificial night glow, and obtrusive light; protect the local natural ecosystem from damaging effects of artificial lighting; and encourage quality lighting design and fixtures. ... (5)All lighting shall have a nominal correlated color temperature (CCT) of no greater than 3000 Kelvin. Consider high color fidelity lamps relative to the lighting application.(6)Light poles shall be anodized (or otherwise coated) to minimize glare from the light source. ... (G)Prohibited Lighting. The following lighting is prohibited:(1)Site lighting that may be confused with warning, emergency or traffic signals.(2)Mercury vapor lamps.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Municipal Code: Supplement 155 | Transitional Land Use Code (for project before May 17, 2024): Supplement 61 | Traffic Code: Supplement 27).
Full Breakdown
4 of Fort Collins' Transitional Land Use Code required most development proposing outdoor lighting (with limited residential exceptions dated to March 26, 2021) to submit a lighting plan for review. ' Subsection (G) flatly prohibited two categories of fixtures: lighting that could be confused with warning, emergency or traffic signals, and mercury vapor lamps outright. 4-4, and a total-site lumen cap calculated by parking-space count or hardscape area. Temporary construction and holiday lighting, festoon lights under 30 days, right-of-way lighting, and single-family/duplex residential fixtures were exempted under subsection (F).
Fixture additions or upgrades exceeding set thresholds after March 26, 2021 required a Director-level or minor-amendment review limited to the purpose, design-standard and offsite-impact provisions of the Section.
Violations & Fines
Under Land Use Code Section 2.14.4(A), a violation of any Land Use Code standard, including the Section 3.2.4 lighting requirements, is a misdemeanor subject to City Code Section 1-15 penalties, with each day of noncompliance a separate offense; unclassified misdemeanor fines run up to $2,650. A development that installs mercury vapor lamps or exceeds the CCT cap risks denial of its certificate of occupancy until the lighting plan is brought into compliance.
Frequently Asked Questions
Does Fort Collins limit the color temperature of outdoor lighting?
Are mercury vapor lamps allowed in Fort Collins?
Which properties are exempt from the outdoor lighting plan requirement?
Sources & Official References
Other rules in Fort Collins
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Dark Sky Rules in Nearby Cities
How other cities in Larimer County handle dark sky rules.