# Science of the Winter Solstice > Reading Time: 2 minutesScience of the Winter Solstice: what does it mean, how it ushers in Winter > URL: https://billpetro.com/science-of-winter-solstice/ > Last modified: 2025-12-29T19:25:09+00:00 Reading Time: 2 minutes ## SCIENCE OF THE WINTER SOLSTICE [*Podcast version*](https://open.spotify.com/episode/0f9c2aHFuG9Blulz81ZAi6?si=ac7fae8146d3433c)   As I mentioned in my article on [Advent](https://billpetro.com/history-of-christmas-advent), the Romans celebrated a holiday known as the **Saturnalia**, especially during the later Empire period**, **beginning with the **Winter Solstice**. The word Solstice comes from the Latin “*solstitium,*” meaning “Sun, standing still.” This year, it occurs in Greenwich, England (near London), at 3:03 pm GMT (or UTC) on *December 21,* and marks the first day of the Winter season in the Northern Hemisphere from an astronomical perspective.   Table of Contents Toggle - [Seasons](#Seasons) - [Solstice: Standing Still](#Solstice_Standing_Still) - [Solstice and the Roman Saturnalia](#Solstice_and_the_Roman_Saturnalia) - [Know-it-all Facts to Impress Your Friends and Family](#Know-it-all_Facts_to_Impress_Your_Friends_and_Family) - [Related](#Related) ### Seasons Earth experiences different seasons because it is tilted 23 degrees and 27 minutes from the perpendicular to its orbital plane. This means that the world revolves like a *tilted* spinning top. The Winter Solstice is the shortest day of sunlight as the Sun is at its lowest arc in the sky, at least in the **Northern Hemisphere**. The farther north one is from the Equator, the more pronounced the difference in daylight is in Winter. However, as the Earth continues its orbit, the hemisphere that is angled closest to the Sun changes, and the seasons are reversed.   ### Solstice: Standing Still In the Northern Hemisphere, the Sun appears at its lowest point in the sky, and its noontime elevation appears to be the same for several days before and after the Solstice. In this way, it appears the Sun is “standing still” from the perspective of someone standing on Earth until, after the Winter Solstice, the days begin to grow longer and the nights shorter. In **London,** for example, on the Winter Solstice, the Sun sets at 3:53 pm, and the “day” is only 7 hours and 50 mins long**.**   The Breathing Earth: A year of seasonal transformations on our planet, including the December solstice. John Nelson created this animation using images from the NASA Visible Earth team.   ### Solstice and the Roman Saturnalia I’ve written previously *[here](https://billpetro.com/history-of-christmas-traditions)* and *[here](https://billpetro.com/history-of-mistletoe)* about how the Romans celebrated *Saturnalia* around this time of year, honoring *Saturn* as the head of their pantheon of Titans. *Saturday* gets its name from **Saturn**.   ### Know-it-all Facts to Impress Your Friends and Family It is called the “shortest day of the year” or the “extreme of winter,” though it *begins* the start of Winter. You cast your longest shadow at noon on this day. It has the fewest hours of sunlight and the most hours of darkness. - **New York City**: 9 hours, 15 minutes of sunlight - **Helsinki, Finland**: 5 hours, 49 minutes of sunlight - **Barrow, Alaska**: 0 minutes of sunlight — *no sunrise at all* until January 22   Ironically, despite being the “shortest day” of the year, for people living in the US, you’ve already endured the earliest *sunset* of the year. - In **Caribou, Maine**, on the eastern edge of the Eastern Time Zone, the Sun dips below the horizon at 3:43 p.m. from December 8 to 12. - In **New York City**, the sunset is at 4:28 between December 3 and 12. - However, in **Key West, Florida**, it’s 5:38 p.m., occurring between November 23 and December 5.   *It’s all about your latitude.*   Bill Petro, your friendly neighborhood historian [billpetro.com](https://billpetro.com) *Podcast version* [*Subscribe*](http://g003.enterprise.ipost.com/billpetrofriend/prefs) to have future articles delivered to your email. ### *Related* [](https://www.addtoany.com/add_to/facebook?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-winter-solstice%2F&linkname=Science%20of%20the%20Winter%20Solstice)[](https://www.addtoany.com/add_to/x?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-winter-solstice%2F&linkname=Science%20of%20the%20Winter%20Solstice)[](https://www.addtoany.com/add_to/pinterest?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-winter-solstice%2F&linkname=Science%20of%20the%20Winter%20Solstice)[](https://www.addtoany.com/add_to/linkedin?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-winter-solstice%2F&linkname=Science%20of%20the%20Winter%20Solstice)[](https://www.addtoany.com/add_to/mastodon?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-winter-solstice%2F&linkname=Science%20of%20the%20Winter%20Solstice)[](https://www.addtoany.com/add_to/threads?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-winter-solstice%2F&linkname=Science%20of%20the%20Winter%20Solstice)[](https://www.addtoany.com/add_to/bluesky?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-winter-solstice%2F&linkname=Science%20of%20the%20Winter%20Solstice)[](https://www.addtoany.com/add_to/reddit?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-winter-solstice%2F&linkname=Science%20of%20the%20Winter%20Solstice)[](https://www.addtoany.com/add_to/tumblr?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-winter-solstice%2F&linkname=Science%20of%20the%20Winter%20Solstice)[](https://www.addtoany.com/add_to/kindle_it?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-winter-solstice%2F&linkname=Science%20of%20the%20Winter%20Solstice)[](https://www.addtoany.com/add_to/snapchat?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-winter-solstice%2F&linkname=Science%20of%20the%20Winter%20Solstice)[](https://www.addtoany.com/add_to/email?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-winter-solstice%2F&linkname=Science%20of%20the%20Winter%20Solstice)[](https://www.addtoany.com/add_to/print?linkurl=https%3A%2F%2Fbillpetro.com%2Fscience-of-winter-solstice%2F&linkname=Science%20of%20the%20Winter%20Solstice)[](https://www.addtoany.com/share)