As you put on your coat, gloves and scarf, you may be wondering why it is so cold in the winter and why summers are hot. What gives? It all has to do with the earth and the sun … but not in a way that most people think. To help us answer this question, we turn to Everyday Mysteries.
The first thing to understand about seasons is that in the southern hemisphere (the southern half of the earth), the seasons are opposite of the northern hemisphere (the northern half of the earth). They still call their cold season “winter’ and warm season “summer,” but while those of us in America are bundling up to protect from the freezing winter weather, our Australian friends are in the middle of their summer!
Understanding how seasons work in different hemispheres helps us explain a common misconception. Many people incorrectly think that the earth is further away from the sun in the winter, therefore making it colder. This is not the case. If seasons were determined by the distance of the sun (our heat source) to our planet, then the southern hemisphere and northern hemisphere would have the same seasons at the same time.
Instead, seasons are explained by the tilt of the earth. Our planet sits at a 23.5-degree angle in space. As the earth travels around the sun in its 365-day journey, some parts of the surface point directly at the sun at different times.
When the northern hemisphere is pointed toward the sun, sunlight hits more directly, and it warms up this part of the earth. In the winter, when the northern hemisphere is pointed away from the sun slightly, the sun’s rays come in at an angle and have less of an impact. This makes winter cold!
Looking for more Never Stop Asking "Why?" questions? Catch up on all of the past "Why's" on the blog!