Saturday night, Dec. 21st will be the longest night of the year -- it will be Winter Solstice in the Northern Hemisphere. This means that North America will get only 9 hours and 32 minutes of sunshine as the night stretches on for more than 14 hours of darkness. The solstice will begin at 12:11 p.m. on Saturday.
During this time, the sun will be overhead along the Tropic of Capricorn, at 23.5 degrees south. Locations north of the equator will see the sun follow its shortest arc across the southern sky. The Earth's North Pole will be at its maximum tilt away from the sun. In Washington DC, the sun will be above the horizon for 9 hours and 26 minutes but the day will be even shorter for cities in Canada that are closer to the Northern Pole.
The opposite will be the case in the Southern Hemisphere, as Earth's South Pole will be pointing towards the sun, thus the Southern Hemisphere will have its longest day.
After Dec 21, the nights will again start becoming shorter because the sun spends more time on the horizon until March 20 when there will be the same length of day and night because the axis of the Earth will be vertical.
Again, the days will continue to grow longer through to the summer, and on June 21, we’ll experience the longest day of the year.
Watch video of a short Arctic day