Winter solstice has arrived — the day Australia experiences its shortest amount of daylight in the whole calendar year.

Each winter solstice, thousands of swimmers in Tasmania turn out to mark the day with a freezing dip in Hobart’s beach.

More than 3,000 people took part in the event on Saturday morning, which is also the final event for Hobart’s Dark Mofo winter feast festival.

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Saturday is the day the Southern Hemisphere is officially at its furthest tilt away from the sun, meaning all Australians experience a much shorter day, followed by the longest night into Sunday.

At the same time, the Northern Hemisphere is celebrating the opposite, with the longest amount of daylight followed by the shortest night.

Earth is currently sitting at a tilt of 23 degrees, meaning the Southern Hemisphere is the furthest away from the sun it will get all year.

Earth rotates around an axis —a line from the North Pole to the South Pole, through the centre of the Earth once every 24 hours and we orbit the Sun once every year.

Our rotation axis is tilted relative to the plane of our orbit around the Sun.

The hours of daylight Australians see today, also may vary today, with BOM expecting those who are more south to experience a shorter day.

Hobart, for example, only sees around nine hours of daylight at the winter solstice — but 15 hours of daylight at the summer solstice.

While in Darwin and other Queensland towns at the top of Australia, daylight hours can vary from 11.5 hours of daylight at the winter solstice to about 12.5 hours of daylight at the summer solstice.

The change to the amount of daylight Australians experience on each solstice can also have a significant impact on sleeping patterns with health experts encouraging people to avoid sleeping in so they can maintain their body clock.