Seasons

Periods of time in which is the year is divided, and that in places away from the equator are easily distinguished by changes in the weather and vegetation.

The cause of the seasons is the inclination that the axis of the earth has respect to the axis of its orbit around the sun. As a consequence, the angle with which the sun's rays impact the surface of the earth varies with the position of the earth in its orbit. The rays lose more energy when they pass through the atmosphere longer distances.

(more later)