Both the North Pole and the South Pole can be divided into eternal day and eternal night. In a year, there are six consecutive months of daylight (this endless daylight phenomenon is called extreme daylight) and six months of darkness (this endless darkness phenomenon is called extreme night).

During the perpetual night (polar night) of one month, the moon is bright (full moon or absent) for 1 5 days, and not bright for 1 5 days.