Western Governors University (WGU) SCIE1020 C165 Integrated Physical Sciences Practice Exam

The primary reason for the seasonal weather changes experienced on Earth is the tilt of the Earth on its axis. This axial tilt, at an angle of approximately 23.5 degrees, causes different parts of the Earth to receive varying amounts of sunlight throughout the year. As the Earth orbits the Sun, this tilt results in the changing seasons.

During summer in the northern hemisphere, that hemisphere is tilted towards the Sun, leading to longer days and more direct sunlight, which causes warmer temperatures. Conversely, during winter, the northern hemisphere is tilted away from the Sun, resulting in shorter days and less direct sunlight, leading to cooler temperatures. The opposite occurs in the southern hemisphere.

While other factors like distance from the Sun, atmospheric pressure, and ocean currents play important roles in weather patterns and climate, it is the axial tilt that primarily dictates the seasonal variations we observe.