Antarctic << ant AHRK tihk or ant AHR tihk, >> Circle, is an imaginary line that encloses almost all of Antarctica. Points on the Antarctic Circle lie at 66° 33′ south latitude, about 1,624 miles (2,613 kilometers) from the south geographic pole.
The Antarctic Circle marks the edge of an area where the sun stays above the horizon one or more days each year. The sun never sets on the Antarctic Circle during the longest day of summer, about December 21. The sun never rises on the shortest day of winter, about June 21. If the South Pole at 90 degrees south latitude were at sea level instead of nearly 10,000 feet (3,000 meters) above sea level, and if no atmospheric phenomena or other obstacles affected observations, the sun would be visible 90 days before and 90 days after the longest day of summer. It would stay below the horizon for the same time before and after the shortest day of winter.
