great circle that divides a spheroid into northern and southern hemispheres, particularly that line for the planet Earth

The equator is a line which is not real drawn around a sphere or planet, such as the Earth. It is one of the lines known as a line of latitude, or circle of latitude. The name "equator" is Latin for "even-maker"; at equator the day and night are exactly the same length around the year.

How the Sun lights the Earth on the day of equinox
Map of Earth showing the equator and other major lines of latitude

The equator is halfway between the North Pole and the South Pole. There, the surface of the planet is parallel to the axis of rotation. The equator divides the surface into the northern hemisphere and the southern hemisphere.

Climate change

Unlike the northern hemisphere and the southern hemisphere, countries around the equator do not experience the four seasons, and the climate is usually very humid.

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