Antarctic Circle

The Antarctic Circle is the circle of latitude that is approximately 66.5 degrees south of the Earth's equator and that circumscribes the southern frigid zone. It marks the latitude south of which the sun does not rise on the (northern hemisphere) summer solstice or set on the (northern hemisphere) winter solstice. That is, south of the Antarctic Circle, there is at least one day when the sun never rises in Southern Hemisphere winter months and at least one day when never sets in the summer.

Everything south of this circle is known as the Antarctic, and the zone the north of this circle is the Southern Temperate Zone.