the entire day. This happens when the sun is between 18° and 23° 26’ below the horizon. These conditions last about 11 weeks at the poles. The South Pole, Antarctica experiences this from May 11 to August 1 or August 2 depending on the year. The North Pole experiences this from November 13 to January 29. Polar Sun cycle If an observer located on either the North Pole or the South Pole were to define a "day" as the time from the maximal elevation of the Sun above the horizon during one period of daylight, until the maximal elevation of the Sun above the horizon of the next period of daylight, then a "polar day" as experienced by such an observer would be one Earth-year long. See also Midnight sun References Further reading External links The polar night and polar darkness Many years' of webcam pictures from Tromsø, Norway. These clearly show the progression into and away from winter at a latitude within the Arctic Circle. Earth phenomena Polar regions of the Earth Night