South Pole
In midsummer, as the sun reaches its maximum elevation of about 23.5 degrees, high temperatures at the South Pole in January average at . As the six-month "day" wears on and the sun gets lower, temperatures drop as well: they reach around sunset (late March) and sunrise (late September). In midwinter, the average temperature remains steady at around . The highest temperature ever recorded at the Amundsen–Scott South Pole Station was on Christmas Day, 2011, and the lowest was on June 23, 1982 (for comparison, the lowest temperature directly recorded anywhere on earth was at Vostok Station on July 21, 1983, though was measured indirectly by satellite in East Antarctica between Dome A and Dome F in August 2010). Mean annual temperature at the South Pole is -49.3 °C (-56.7 °F).
Amundsen–Scott South Pole Station
Research at the station includes glaciology, geophysics, meteorology, upper atmosphere physics, astronomy, astrophysics, and biomedical studies. In recent years, most of the winter scientists have worked for the IceCube Neutrino Observatory or for low-frequency astronomy experiments such as the South Pole Telescope and BICEP2. The low temperature and low moisture content of the polar air, combined with the altitude of over , causes the air to be far more transparent on some frequencies than is typical elsewhere, and the months of darkness permit sensitive equipment to run constantly.