Why Do We Have Seasons?

righttilt1One of the most misunderstood concepts in science is the answer the to question: Why do we have seasons?  Many people, even very educated people, have strange misconceptions about this natural phenomenon.  In the late 1980’s a documentary called  “A Private Universe” was made about student misconceptions in science.

Click here to see a short preview of the video  “A Private Universe” and then read on to learn the real reason we have seasons.    A Private Universe Preview

We have seasonal weather changes because of three reasons (and none of them are because the Earth is closer to the sun). The three reasons why we have Seasons are:


  • The Earth’s axis is tilted at an angle of 23.5 degrees. This means that the Earth is always “pointing” to one side as it goes around the Sun. So, sometimes the Sun is in the direction that the Earth is pointing, but not at other times. The varying amounts of sunlight around the Earth during the year, creates the seasons.
  • Revolution – The Earth revolves around the Sun. The Earth takes 365.24 days to orbit the sun. As we move around the Sun during the year, the amount of light each area of the planet receives varies in length.
  • The North Pole always POINTS in the same direction.  The North pole always points the same way as the Earth revolves around the Sun.

It is winter time in countries in the Northern Hemisphere.  It is summer time in countries in the Southern Hemisphere. During the summer, the sun’s rays hit the Earth at a steep angle because the sun is higher in the sky. The light does not spread out very much, thus increasing the amount of energy hitting any given spot. During the winter, the sun’s rays hit the Earth at a shallow angle because the sun is lower in the sky. These rays are more spread out, which minimizes the amount of energy that hits any given spot. http://youtu.be/DuiQvPLWziQ Why do we have seasons video.