Find out how the Earth's tilt throughout its orbit causes Earth's seasons.
Source:OurAmazingPlanet

In the spring or autumn, the pole is tipped neither toward or away fro the sun. Days and nights are about equal in length. These times are called equinoxes.

As the seasons change, the apparent path of the sun in the sky changes. In summer, the sun arcs high, and the days are longer than the nights. In winter, the sun’s path is lower, and the nights are longer than the days.

These seasonal changes happen because our planet is tipped at a jaunty angle as it orbits the sun. Our axis of rotation is permanently jilted at the angle of 23.4 degrees. As the year progresses, one or the other of the Earth’s poles tips toward the sun. For the half of the Earth receiving the most solar energy, this is summer. Six months later, the pole tips away from the sun, solar energy is at its lowest, and this is called winter. These points of highest and lowest solar energy are called the solstices.