Countries located in the polar regions like Alaska in USA, Greenland, Norway, Finland, Siberia regions of Russia in the North Pole and Antractica in the South Pole have six months day and night instead of normal 12 hours duration.

In the north pole area, during 21st March to 23rd September it is day time, while it is night in the South Pole. The reverse happens from 23 September to 21st March in North and South Poles due to movement of earth around the sun in a 66° sloping direction. This makes some regions of earth moving away from the sun during different periods of the year and some regions come nearer.