Ever heard of the winter solstice? It’s a pretty cool astronomical event that marks the shortest day and longest night of the year in the Northern Hemisphere. Think of it as the official start of winter! But what exactly is it, and when does it happen in 2024? Let’s break it down in a friendly way.
For those of us in the Northern Hemisphere, the arrival of December often comes with colder weather and the anticipation of the holiday season. While winter’s chill may have been in the air for weeks, the official start of the astronomical season arrives not with a date on the calendar but with a celestial event known as the solstice.
In December 2024, that moment will mark the shortest day of the year for the Northern Hemisphere—and the longest day in the Southern Hemisphere.
What Is the Winter Solstice?
The word “solstice” comes from Latin words meaning “sun stands still.”
On a solstice, the sun’s path across the sky appears to reach its most extreme position—either its northernmost or southernmost point—before reversing direction.
In June, the Northern Hemisphere sees its longest day of the year (and the Southern Hemisphere its shortest). In December, the opposite occurs: The Northern Hemisphere experiences its shortest day and longest night.
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This seasonal swing is all thanks to Earth’s tilt. Our planet sits at an angle of about 23.5 degrees relative to its orbital plane around the sun. Because of this tilt, the amount of sunlight different parts of Earth receive changes throughout the year, creating the seasons.
When the Northern Hemisphere tilts away from the sun, it gets fewer hours of direct sunlight and experiences winter.
When Is the Winter Solstice 2024?
This year’s December solstice occurs on Saturday, Dec. 21, 2024, at 4:19 a.m. EST.
At that precise moment, the sun will shine directly over the Tropic of Capricorn, an imaginary line circling the Earth at about 23.5° south latitude. For viewers in the Northern Hemisphere, the solstice represents the point at which the sun reaches its lowest position in the midday sky.
If you’re living far north, by December, you’ve already noticed the days becoming shorter and the nights creeping in early. The winter solstice is simply the day this trend reaches its maximum. After it passes, you can look forward to gaining a little more daylight each day, even if the weather won’t warm up right away.
Why Does the Winter Solstice Happen?
It’s easy to assume that the seasons depend on our planet’s distance from the sun, but that’s not true. Earth’s orbit is slightly elliptical, sometimes closer or farther from the sun. However, that difference isn’t what drives the seasons. Instead, it’s the tilt of the Earth’s axis.
Imagine Earth as a spinning top, tilted at 23.5 degrees. As it revolves around the sun, different hemispheres lean toward or away from the sun’s rays.
In December, the Northern Hemisphere is tilted away, receiving less direct sunlight and shorter daylight hours. Meanwhile, the Southern Hemisphere tilts toward the sun, enjoying their summer with long, warm days.
Perihelion and Aphelion
While distance isn’t the reason for the seasons, it’s interesting that Earth’s closest approach to the sun (called perihelion) happens just a few weeks after the December solstice, around Jan. 3, 2025. That’s right—when it’s winter in the Northern Hemisphere, Earth is a tad closer to the sun, not farther.
Conversely, during the summer in the Northern Hemisphere, Earth is actually at aphelion, its farthest point from the sun.
This might seem counterintuitive, but it makes sense once you remember that tilt is what counts. The sun’s rays are hitting the Northern Hemisphere at a steeper angle and for fewer hours in winter, making it colder despite Earth’s slightly closer proximity.
How Long Is the Shortest Day of the Year?
The exact length of the shortest day depends on where you live. The further north you go, the shorter the daylight hours become. Here are a few examples:
- New York, USA: about 9 hours and 15 minutes of daylight
- Los Angeles, USA: about 9 hours and 53 minutes of daylight
- London, UK: about 7 hours and 49 minutes of daylight
The difference is even more dramatic for those living much closer to the Arctic. Some far northern regions experience just a few hours of very low sunlight or even none at all, known as the polar night. In contrast, if you’re in the Southern Hemisphere—say in Australia or Argentina—this is your longest day of the year, and you’ll bask in extra hours of sunlight.
What Happens After the Solstice?
Once the winter solstice has passed, the Northern Hemisphere begins its slow journey back toward longer days.
You might not notice the change immediately since the initial increments are small. Nevertheless, you’ll have a few more minutes of daylight by early January. As the weeks pass, the pace of day-length gain increases. By the time spring arrives, the difference will be undeniable.
It’s worth noting that temperatures often lag behind daylight changes. While the days start lengthening right after the solstice, Northern Hemisphere winters typically reach their coldest weeks in January or February.
This lag is due to the Earth and atmosphere’s ability to store heat. Even though we’re gaining daylight, it takes time for the environment to warm up.
Tips for Observing the Solstice
While the solstice isn’t as visually dramatic as an eclipse or a meteor shower, there are still ways to mark the occasion:
- Watch the Sunrise or Sunset: On the solstice, the sunrise and sunset follow their most extreme southward paths (in the Northern Hemisphere). Observing these can help you notice how the arc of the sun’s daily journey is different now compared to summer.
- Track Daylight Changes: Keep track of sunrise and sunset times for a few weeks before and after the solstice. Watching how the daylight period changes can be a fun, low-key science experiment to appreciate Earth’s seasonal rhythms.
- Celebrate a Festival or Tradition: Many cultures have special traditions for the solstice. Whether lighting candles, telling stories, or enjoying a warm drink with family, consider creating your small ritual to honor the changing seasons.
- Enjoy the Night Sky: The longest night is an excellent opportunity for stargazing, as darkness comes early and lingers. Bundle up, grab a telescope or binoculars if you have them, and enjoy the crisp winter sky. The night sky feels even more prominent and special with fewer daylight hours.
Why Does the Solstice Matter Today?
Culturally and historically, the winter solstice has been celebrated by many cultures as a significant moment. Since this day marks the shortest amount of daylight, it is often symbolized as a day of rebirth and renewal. After the solstice, the sun’s path shifts northward, slowly lengthening the days.
Ancient peoples noticed this and often held festivals to mark the “return of the light.”
In many traditions, the solstice signaled hope: though the heart of winter might still lie ahead, each new day after the solstice brought a little more daylight. Festivals like Yule in northern Europe and various solstice observances worldwide continue today, honoring the cycle of seasons and the interplay between darkness and light.
In our modern, technology-filled world, it’s easy to forget just how much the cycle of seasons influenced the lives of our ancestors. But even today, the solstice marks an astronomical milestone that reminds us of our planet’s constant motion around the sun. It ties us to a grand cosmic rhythm that has guided farming, navigation, and cultural festivities for millennia.
For many, the solstice is a comforting reminder that time marches on and that the darkness of winter is only temporary. From this point forward, each new dawn brings a little more light. That’s a hopeful message as we move past the yearend of the year and into the next calendar year.
The winter solstice of 2024 occurs on Saturday, Dec. 21, at 4:19 a.m. EST, officially marking the start of winter in the Northern Hemisphere and summer in the Southern Hemisphere.
Though we’ve felt winter’s cold for weeks, this celestial moment confirms our place in the seasonal cycle. After the solstice, days slowly lengthen in the north, symbolizing a return of the light. With its cultural significance, subtle atmospheric changes, and connection to our planet’s tilt and orbit, the solstice remains a profound reminder of nature’s steady rhythms, no matter how modern our lives become.
So, this December, when the sky seems dark and the days short, remember that the winter solstice is a turning point. The Earth keeps spinning, the sun’s position will shift again, and brighter days are literally on the horizon.
