Why Do We Have Seasons?

Our planet rotates on its axis (AK-sis), an imaginary line that runs from earth’s “top” to “bottom.” The earth makes one complete rotation every 24 hours. When earth faces the sun, we experience day. When earth spins away from the sun, we experience night.

Earth also orbits (circles) the sun about every 365 days. Thanks to earth’s tilt, orbit, and spin, we have seasons.

But we don’t all experience the same seasons at the same time. For example, when people in the United States are experiencing summer, people in Argentina are experiencing winter. That’s because earth is divided into hemispheres (HEH-mih-sfeers). The top is the northern hemisphere, and the bottom is the southern hemisphere.

During earth’s journey around the sun, sometimes the north pole is tilted toward the sun and sometimes the south pole is tilted toward the sun. Whichever hemisphere points closer to the sun during earth’s orbit experiences summer because the sun shines on that area more directly. When a hemisphere points farther away from the sun, it experiences winter because the sun shines on that area less directly.

The seasons start on different dates in the two hemispheres. For example, in the southern hemisphere, winter starts in June (when the south pole is tilting away from the sun) and summer begins in December (when the south pole is tilting toward the sun). That means Christmas day in Australia is often over 100ºF!

God put these cycles in place during creation week. Genesis 8:22 says, “While the earth remains . . . summer and winter, day and night, shall not cease.” Though the weather might change, we can trust that the seasons will continue until Jesus returns and creates a new heaven and earth.

A Closer Look

January

When the north pole tilts away from the sun, it’s winter in the northern hemisphere and summer in the southern hemisphere.

March

Spring arrives in the northern hemisphere when the poles start tilting toward the sun.

July

Summer comes in the northern hemisphere when the north pole is pointed most directly at the sun. Meanwhile, it’s winter in the southern hemisphere.

October

Fall hits the northern hemisphere when the north pole switches from tilting toward the sun to tilting away.

Equinoxes

Twice a year, the sun shines equally on both hemispheres. These days are called equinoxes (EE-kwih-nocks-es). The vernal equinox in March marks the start of spring in the northern hemisphere and autumn in the southern hemisphere. The autumnal (ah-TUHM-nuhl) equinox in September marks the start of autumn in the northern hemisphere and spring in the southern hemisphere.

Solstices

A solstice is a day when the sun’s path in the sky is farthest north or south from earth.

The winter solstice in December, when the sun shines more directly on the southern hemisphere, marks the start of winter in the northern hemisphere and summer in the southern hemisphere.

The summer solstice in June, when the sun shines more directly on the northern hemisphere, marks the start of summer in the northern hemisphere and winter in the southern hemisphere.