Middleton, WI Outdoor Lighting: Dark Sky Rules (2026)

Chapter 33, adopted by Ord. No. O1671 on March 3, 2026, states its purpose is to prevent harmful sky glow and 'preserve the naturally dark sky for the benefit of residents, visitors, wildlife, and the environment' (Section 33.01). It defines a 'Fully Shielded' luminaire as one that emits no light, directly or indirectly, at or above a horizontal plane through its lowest light-emitting part (Section 33.03). Any luminaire over 1,000 lumens must be Fully Shielded and may emit no more than 5 percent of its total output above 80 degrees from Nadir, with narrow exceptions for low-output festoon string lighting and shielded facade illumination (Section 33.07(1)(c)).

Outdoor fixtures also may not exceed a maximum color temperature of 3,000 Kelvin absent a documented public safety need (Section 33.07(1)(g)), must be LED, and may not mount above the roofline except for motion-activated security or architectural accent lighting (Section 33.07(1)(h)). Non-essential lighting, including landscape and decorative lighting, must go dark during Nighttime Hours, defined as 10 p.m. to sunrise or one hour after closing for late businesses (Section 33.07(1)(e), Section 33.03). The rules apply to lighting installed or replaced after March 3, 2026; existing fixtures are legal nonconforming until the property is rezoned, its use is abandoned for six months, or the Building Inspector finds a safety hazard (Section 33.04(2)). The Plan Commission may grant exemptions during site plan design review (Section 33.05(6)).