Daytime

Daytime is the period of the day in which the Sun is above the local horizon in a given location. It is sometimes just called "day". During the daytime an area is illuminated by daylight, a combination of direct sunlight and indirect light from the sky. At any given time, about half of the Earth is facing the Sun and experiencing daytime. The length of daytime varies with latitude and changes over the course of the year, as the Earth moves around the Sun. Other planets and natural satellites that rotate relative to a luminous primary body such as a local star also experience daytime, but this article primarily discusses daytime on Earth.