The Reason for the Seasons: The Solstice

Updated: Jan 24

Do you love all the different seasons? Do you enjoy jumping in a pile of leaves in fall, sledding down a snow-covered hill in winter, smelling fresh blooming flowers in spring and chasing fireflies in summer?

A winter sunset at Whalon Lake. (Photo courtesy of Nancy Havener)

The changing of the seasons happens because of the special way Earth works. The winter solstice is an example of Earth’s magic … and science!


What is the winter solstice?


The winter solstice is December 21, so we’re creeping up to it right now. As we get closer to the date, the days start to feel like they are shorter. We still have 24 hours in a day, but the amount of daylight each day is getting shorter and shorter. It is dark before dinnertime!

(Graphic via Shutterstock)

The winter solstice is the day with the shortest amount of daylight and the longest night of the year. Here in Will County we only get about eight hours of sunlight on the day of the winter solstice. That means we have 16 hours of darkness!


How does it happen? It’s all about how the Earth moves around in space. Let’s break it down.


  • Each year, Earth makes a full circle around the sun.

  • Earth also has an imaginary line running from the North Pole to the South Pole that we call the axis. While the Earth is spinning around the sun, it is also spinning around its axis. One turn around the axis equals one day.

  • The axis is not straight up and down. It is tilted just a bit. In the summertime, the top of the globe (the northern hemisphere, where we live) faces toward the sun. As a result, we have more hours of daylight each day. The opposite happens in winter. Earth’s axis is tilted away from the sun, giving us fewer daylight hours.

  • Did you know it’s not just the amount of daylight that matters? The tilt toward the sun means direct sunlight heats up the Earth. That’s summertime! The tilt away from the sun means weaker sun rays. Hello, winter. Try it with your hand. The top is the northern hemisphere and the bottom is the southern hemisphere. From a safe distance, tilt the top of your hand toward a campfire or a lamplight. Now tilt your fingertips away from the heat. What do you notice?

  • The winter solstice is the day with least amount of daylight, which is why we call it the shortest day of the year. This year it happens on December 21. On the December 22, daylight will last a little longer each day until we reach the day with the most amount of daylight. That day is the summer solstice, which is around June 20 each year.


It’s dark! Now celebrate!


We now know the science of the winter solstice. But for people who lived a long time ago, the solstice must have been a little scary. The sun would disappear earlier and earlier each day. Could it disappear forever? Ancient civilizations came up with fun ways to combat the darkness.


The Romans celebrated the solstice with a festival called Saturnalia. There was lots of feasting, and people gave gifts. The roles were switched, and servants got to be in charge for the day. Early Scandinavians lit huge bonfires to ward off the darkness and feasted to celebrate the solstice. Closer to home, Cahokians lived about where St. Louis, Missouri, is now. They built a large monument called Woodhendge on top of a huge mound to welcome the solstice sun every year.


Enjoy the 2019 solstice


The extra hours of darkness as the winter solstice approaches are great for outside fun with your friends and family! Build a nighttime winter campfire and enjoy treats around the flames. Suit up in winter gear and check out the stars. Play winter flashlight tag. Whatever you do, take advantage of the season.

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