Photo by Jesse Allen, NASA’s Earth Observatory.

Americans love their holiday lights. It’s a scientific fact.

NASA scientists looked at data from the NOAA/NASA Suomi National Polar-orbiting Partnership satellite to analyze if and by how much nighttime lights shine brighter around major U.S. cities in December. That number was between 20 and 50 percent in some U.S. cities, with the biggest increase shown in dark green on the above and below maps.

Photo by Jesse Allen, NASA’s Earth Observatory.

“It’s a near ubiquitous signal. Despite being ethnically and religiously diverse, we found that the U.S. experiences a holiday increase that is present across most urban communities,” Miguel Román, a NASA Goddard research physical scientist who worked on the project, said. “These lighting patterns are tracking a national shared tradition.”