The winter solstice occurs in December, and the date marks the 24-hour period with the fewest daylight hours of the year in the northern hemisphere. This is why the winter solstice is known as the shortest day or longest night of the year. In 2019 the winter solstice will occur on Sunday, December 22.
What is the winter solstice?
Because the Earth is tilted on its axis, the arc the Sun moves through during the day will rise and fall across the year as the Earth’s pole points either towards or away from the star.
The winter solstice occurs at the minimum point for the northern hemisphere, when the Sun is lowest in the sky.
At this time, the Earth’s North Pole is pointing away from the Sun, the reason why it is so much colder in the northern hemisphere.
For people living in the southern hemisphere, the South Pole is pointing towards the Sun, making it summertime on the other side of the planet.
After the shortest day, the days start getting longer and the nights shorter.
At the spring and autumnal equinoxes the day and night hours are approximately the same length, each lasting around 12 hours.
The number of daylight hours peaks during the summer solstice.
The world “solstice” comes from the Latin solstitium meaning “Sun stands still”.
This is because the apparent movement of the Sun’s path north or south stops before changing direction.
At the winter solstice, the apparent position of the Sun reaches its most southerly point against the background stars.
Opinion is divided over whether the solstice marks the start of winter or the middle of winter, or whether winter actually starts on December 1 – as reckoned by most meteorologists.
One reason for the confusion comes from the lag in changes in temperature and weather patterns.
These mean the coldest temperatures during the day are generally felt some time after the shortest day has passed.