A day is still 24 hours. The sun may not rise or set during that period.
Zero, night lasts all day long at the north pole in December.
24 Hours. On summer solstice the earth is tilted toward the sun and it shines continuously at the north pole.
Twenty-four hours of daylight.
The North pole
At either pole, there are several weeks each year that the sun never rises, and several weeks that it never sets. In general, the length of daylight at the North Pole is approximately 24 hours minus the length of the same day at the South Pole. If the North Pole gets 16 hours of daylight, the South Pole gets about 8 hours. If the North Pole gets 2 hours of daylight, the South Pole gets about 22. On the equinoxes, each pole gets 12 hours of daylight and 12 hours of night.
Zero. At the north pole, the sun sets around September 23, and it doesn't rise again until March 21.
The North Pole has 24 hours per day of sunlight from the Spring Equinox until the Fall Equinox.
24 Hours of straight sunlight
Around the north pole in the (northern hemisphere) summer.
At the north pole, the longest day of the year is six months long. The sun is up continuously, in the sky, above the horizon, and does not set for 6 months. And June 21 is the day right in the middle of that period.
The South Pole will get 24 hours of daylight during the Summer Solstice in December. The North Pole will get 24 hours of daylight during the Summer Solstice in June.
winter