Summit County and Park City adopted dark skies ordinances in 2019 and 2021 respectively.
The different ordinances took effect immediately for new lights, but existing lighting has until the end of this year to switch over. Both ordinances require all outdoor bulbs be 3000 Kelvin.
In unincorporated Summit County, all outdoor fixtures must be fully shielded and pointed downward by the end of the year.
Daylight is approximately 6000 Kelvin. 3000 Kelvin and below is typically considered “warm light.”
Seasonal holiday lighting is allowed. In Park City, holiday lighting must be off by 11 p.m.
“It's part of the culture of a mountain town," Summit County Councilmember Roger Armstrong said.
Eastside Summit County residents can use brighter lights in agricultural facilities, as long as they’re shielded and down-facing. Click here for western Summit County exemptions.
The penalty is a code violation, and the city or county would require lighting to come into compliance.
Besides preserving the stars, the rules may benefit residents’ circadian rhythms and local wildlife.
“Maybe you're somebody who loves birds, and other animals and species that are impacted by excessive light at night, which contributes to bird strikes on buildings and impacting migration patterns,” Summit County Sustainability Program Manager Emily Quinton said at the April 3 council meeting.
Scientists believe migratory birds use stars to navigate. And whiter light causes more issues for them than warmer light.
The deadline to switch to compliant lighting is Dec. 31.
The county will update summitcounty.info/darkskies with more information, including how to dispose of or recycle old bulbs. For Park City, visit engageparkcity.com/dark-sky/.