Winter solstice is that period of the year when the Earth's pole tilts away from the Sun, and the Sun's maximum elevation in the sky is at its lowest. Winter solstice occurs two times in a year, once in each hemisphere, i.e., the Northern and Southern hemisphere of our beloved planet, Earth. Winter solstice occurs in December between December 20 and December 23 every year in the Northern Hemisphere, and it occurs in June, usually between June 20 and June 22 every year in the Southern hemisphere.
It is essential to know that winter solstice is also the shortest day of the year because it is the day with the least amount of daylight and the longest night. In the Northern hemisphere, based on Coordinated Universal Time (UTC), the winter solstice was on Sunday, December 22, 2019, and on Monday, December 21, in the year 2020.