By 
October 5th, 2025
Image credit: ESO/P. Horálek
A new study has identified the most light-polluted areas in the United States.
The results stem from a combination of factors to establish a “light pollution index,” ranking cities from the most to the least light-polluted.
A data point from the study: about 80% of Americans can no longer see the Milky Way from where they live because of light pollution.
Night brightness
The study by Overnight Glasses, an eyewear brand, examined the 50 largest US cities, measuring the artificial light brightness at night.
Light levels were calculated both per 100,000 residents and per area, using a light pollution map to ensure that cities could be fairly compared.
Image credit: National Science Foundation
The analysis also considered nightlife, the number of airports and ports, the city’s geography, and local lighting rules.
And the city and state winners are…
Miami, Florida is the most light-polluted U.S. city, with night illumination nearly twice the national average. It is the most light-polluted city in the US, earning an index of 96.2. The city’s nighttime glow has a radiance of 196.3, making its illumination one of the strongest in the country.
California is the most light-polluted state, with three of its cities ranking among the brightest in the country.
Orange sodium vapor lights illuminate the port facilities of Long Beach, California, supporting the round-the-clock operations of one of the world’s busiest commercial cargo ports.
Image credit: NASA
Rhythm of urban life
According to an Overnight Glasses statement: “Light pollution is more than just a glow in the sky; it reshapes how we experience our cities after dark.”
Be it from ports and airports to nightlife and stadiums, the constant brightness reflects “the rhythm of urban life,” the group explains, “but it also comes with consequences for residents, wildlife, and even our ability to see the stars.”
Lastly, the organization notes that prolonged exposure to excessive artificial light can also strain and potentially harm human eyesight.
Image credit: Overnight Glasses
For background information on Overnight Glasses, go to:
Posted in Space News
