According to NASA, Christmas lights up the winter. Using nighttime satellite imagery of American cities, NASA discovered that nighttime lights in American cities shine 20 to 50 percent brighter during the Christmas season than at other times of the year. In Even from Space, Holidays Shine Brightly NASA explains that nighttime lights start getting brighter on the day after Thanksgiving.
You can explore how much brighter your town becomes around Christmas using the interactive map Lights up!. The map shows changes in nighttime lighting by comparing the days before Thanksgiving (November 24–26) with the days after Thanksgiving (November 28–30), 2025. Areas shown in blue became a little brighter, while areas shown in red became much brighter.
These changes are based on satellite measurements of light at night. The data comes from NASA’s VIIRS Black Marble instrument, which detects how bright the Earth appears from space. The instrument detects very small amounts of visible and near-infrared light, allowing scientists to see city lights, towns, roads, and other human-made lighting. By carefully filtering out moonlight, clouds, and other natural sources of brightness, the Black Marble data helps us track how and when people use light, revealing patterns linked to holidays, daily activity, and seasonal changes.
