December 22, is Winter Solstice, the shortest day of the year in the Northern Hemisphere
It is the day when the North Pole is most tilted away from the Sun.
In the Southern Hemisphere, conversely, today is Summer Solstice — in places like Australia, New Zealand, or South Africa, December 22 is the year’s longest day.
This situation will be reversed six months after— on June 21/22, the Northern Hemisphere will see the Summer Solstice when the day will be the year’s longest.
The Earth’s axis of rotation is tilted at an angle of 23.5 degrees away from the perpendicular.
This tilt — combined with factors such as Earth’s spin and orbit — leads to variations in the duration of Sunlight that any location on the planet receives on different days of the year.
