What is the Winter Solstice?
The winter solstice marks the beginning of astronomical winter. It’s different from the beginning of the meteorological winter, which is based on our 12-month calendar.
To answer this question more completely, let’s go back to middle school science class for a minute. The Earth rotates in two primary ways: first, it moves in a big circle around the sun; second, it spins around an axis like a top, creating day and night. That axis is tilted on a slight angle, causing the Northern and Southern hemispheres to receive different amounts of sunlight at different times of the year.
So, though we tend to think about the winter solstice as a day-long event, the term actually refers to a precise moment at which one half of the Earth — either the top or the bottom — is tilted the furthest away from the sun, meaning that that half of the planet sees the fewest hours of sunlight it will see all year.
Though the winter solstice marks the shortest day of each year, it also signals an increase in the amount of sunlight each day for the next six months.
When is the Winter Solstice?
In the Northern Hemisphere, the winter solstice occurs every year on December 21 or 22. This year, it falls on December 21.
The summer solstice is six months later around June 21.
For people who live below the equator, however, those days are flipped. Their winter solstice occurs in June, while their summer solstice happens in December.
What’s an Equinox?
Each year, there are two equinoxes — one in the spring, and one in the fall.
During the equinoxes, the sun is directly above the Earth’s equator, meaning there are equal amounts of sunlight and darkness on those two days.
The vernal equinox, which happens in March in the Northern Hemisphere, marks the astrological end of winter. In September, the autumnal equinox signals the astrological end of summer.
When are the Next Astrological Season Changes?
Below is a list of the astronomical season changes we can expect to see following the upcoming winter solstice next month:
- Vernal Equinox (Spring): Thursday, March 20, 2025, 5:01 a.m.
- Summer Solstice (Summer): Friday, June 20, 2025, 10:42 p.m.
- Autumnal Equinox (Fall): Monday, September 22, 2025, 2:19 p.m.
Can You See the Winter Solstice?
Sort of. Each day, the sun traces a path across the sky, rising in the east and setting in the west. As the winter solstice approaches and the number of hours of sunlight in a day decreases, the sun’s path sinks lower in the sky, though it follows the same general arc.
By the time the winter solstice arrives, the sun sits at the lowest position in the sky it can.
As a result, the shadow you cast becomes longer and longer as the winter solstice approaches. So, while solstices aren’t nearly as visible as eclipses, if you go outside at noon on the winter solstice, your shadow will be the longest it will be all year.
Conclusion
The winter solstice marks the beginning of astronomical winter, and it’s a significant event in the Earth’s rotation around the sun. While it may not be as visible as other celestial events, it’s an important milestone that signals the start of a new season.
Frequently Asked Questions
Q: What is the winter solstice?
A: The winter solstice marks the beginning of astronomical winter, and it’s the shortest day of the year in the Northern Hemisphere.
Q: When is the winter solstice?
A: In the Northern Hemisphere, the winter solstice occurs every year on December 21 or 22.
Q: What’s an equinox?
A: An equinox is a moment when the sun is directly above the Earth’s equator, resulting in equal amounts of sunlight and darkness.
Q: Can you see the winter solstice?
A: Sort of. While solstices aren’t as visible as eclipses, you can observe the sun’s path across the sky and notice that your shadow becomes longer as the winter solstice approaches.
