Cause of Seasons on Earth

It is common knowledge that there are four seasons on Earth. Winter, spring, summer and fall pass each year. But what causes the four seasons?

Cause

The four seasons exist because of the tilt of the Earth on its axis and because of the Earth's orbit around the Sun, according to the National Oceanic and Atmospheric Administration (NOAA). (See Resources.)

Function

The angle of the Sun hitting a particular part of the planet determines which season it is in that area. The planet is warmest where it is hit most directly by the Sun's rays.

Summer

For example, the Sun is the most directly over the northern hemisphere during the summer months, including June, July, August and September, the NOAA says.

Winter

During the winter months, the rays of the Sun are more dispersed, leading to colder temperatures.

Spring and Fall

During the spring and fall, the Sun's rays are not as concentrated as in the summer, but more concentrated than in winter, according to the NOAA.

Fun Fact

The seasons in the northern and southern hemispheres are reversed. When it is winter in the northern hemisphere, it is summer in the southern hemisphere.

Resources

• NOAA and seasons