when is the winter solstice
December Solstice: Shortest day of the year in the Northern Hemisphere. The December solstice is on either December 20, 21, 22 or 23. It is called Winter Solstice in the Northern Hemisphere, where it is the shortest day of the year. In the Southern Hemisphere, it is the Summer Solstice and the longest day of the year. The North Pole is tilted furthest from the Sun.