The direction that a room in the United States has no sunlight is typically the South. This is because the sun follows an east-to-west trajectory throughout the day, with the exception of the equinoxes. During the equinoxes, the sun rises due east and sets due west, but for the majority of the year, the sun's path is more southerly. In the Northern Hemisphere, rooms facing south receive the most sunlight, while rooms facing north receive the least. This is due to the tilt of the Earth's axis, which causes the sun to be lower in the sky during the winter months and higher during the summer months. According to the National Renewable Energy Laboratory, the sun's angle of incidence is at its lowest in the northern hemisphere during the winter, which is why rooms facing north are less likely to receive sunlight.