The 2023 winter solstice arrives on Thursday, Dec. 21, with the Northern Hemisphere marking the shortest day of the year, in which most people in the U.S. will get only about 9 or 10 hours of sunlight, and in parts of Europe even less.

Known also as the "longest night," the solstice this year is at 10:27 p.m. Eastern Time, according to the National Weather Service. 

While the solstice typically occurs on Dec. 21 or 22, it can be as early as Dec. 20 or as late as Dec. 23, the Weather Channel explains. This happens because our calendars aren't an exact match for the solar year.  

As the longest night fades, more sun will be in the forecast as the days begin to get longer bit by bit, until the longest day of the year six months later. The Southern Hemisphere has opposite seasons, so those regions will not observe the winter solstice until June.

The annual event is marked by winter solstice traditions around the world, including parades, festivals, spiritual gatherings and other observances, and thousands of people flock to Stonehenge and other neolithic monuments.

What does the winter solstice signify? 

The winter solstice is the moment when the Earth is the most tilted away from the sun, University of Massachusetts astronomer Stephen Schneider told CBS News in 2017. The closer you are to the Arctic, the shorter the day will be.  

There is a long history of ancient celebrations for the winter solstice, as CBS News previously reported. In ancient Persia, the event marked the birthday of the Sun King Mithra, a mythological deity. In the Roman Empire, it was honored with a feast day known as Die Natalis Invicti Solis, or "The Birthday of the Unconquered Sun." 

Saturnalia, a sort of Thanksgiving, was also celebrated around this time in ancient Rome. 

Many celebrations also include the exchanging of gifts. 

Winter solstice traditions in pictures 

Across the world, the solstice is celebrated with festivals, parades and more. Some of the largest celebrations are held at England's Stonehenge, a neolithic monument that was built to align with the sun on solstice days. On the winter solstice, the sun sets to the southwest of the stone circle.

About 8,000 people attended a summer solstice celebration at Stonehenge in 2023, with over 145,000 more watching on live stream. A similar livestream will be set up for the winter solstice, said the English Heritage charity, which cares for historical sites in England.

Revelers also gather at smaller neolithic monuments like the Newgrange, an ancient burial monument in Ireland. The 5,000-year-old monument was constructed in such a way that sunlight only enters the inner sanctum on mornings around the winter solstice. The central chamber of the monument is lit by the sun as it sets for just 17 minutes a year, according to the monument's website. 

People can enter a lottery for a chance to celebrate the solstice there, and like Stonehenge, the festivities at Newgrange are livestreamed on digital channels. 

Elsewhere in the United Kingdom, the solstice is celebrated with the "Burning The Clocks," a community event that includes a parade and bonfire on the beaches of Brighton. The event is meant to celebrate the shortest day of the year and "provide an antidote to the excesses of Christmas," according to its website, and has taken place almost every year since 1993. 

In Riga, Latvia, the winter solstice is celebrated with a parade and a log-dragging event where a log that represents negative thoughts and misfortunes of the past year is dragged through the city's Old Town and burned. The burning is accompanied by folk songs and dancing, according to local media.  

In Toronto, Canada, the Winter Solstice is celebrated with the Kensington Market Winter Solstice Festival, an annual event that has been going on since 1988. The festival incorporates theatrical elements, street performances and more to create a community event that welcomes the return of the sun. 

Architecture and ancient monuments constructed in alignment with the solstice sun patterns will be aglow. In Egypt, the Karnak Temple, a 4,000-year-old shrine to a sun god, will be lit up by the rising sun and illuminated throughout the day. 

At the Pömmelte ring sanctuary, also known as the "German Stonehenge," dozens of wooden pillars, first constructed 4,000 years ago, will be illuminated by the sun. 

How Southern Hemisphere celebrates the winter solstice

It's currently summer in the Southern Hemisphere, where winter solstice won't arrive till June. But the date is still marked in a variety of ways.

In El Salvador, people gather to burn offerings and take part in other celebrations. 

In Bolivia, the solstice will mark the beginning of a new year in the Andean Amazon calendar. Priests present gratitude ceremonies to the sun and the earth, according to a site outlining tourist attractions in the country; such ceremonies include chants, rituals and burnt offerings. 

There is also a night walk from La Paz to see the sunrise in Tiwanaku, where the solstice is observed. The event is also celebrated at archaeological sites around the country. 

In Cusco, Peru, an event known as the Inti Raymi Sun Festival is held each year to celebrate the solstice. Cusco was once the center of the Incan empire and is near Machu Picchu, which was built by the Incans in 1450 to honor the solstice. 

In:
• Winter Weather

Kerry Breen

Kerry Breen is a reporter and news editor at CBSNews.com. A graduate of New York University's Arthur L. Carter School of Journalism, she previously worked at NBC News' TODAY Digital. She covers current events, breaking news and issues including substance use.

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