What causes the seasons?

The seasons are a result of the 23.5 degree inclination of Earth's rotational axis in relation to the plane around which it orbits the Sun. This tilt means that throughout Earth's orbit around the sun (our calendar year) certain areas of the globe are tilted towards the Sun, while other areas are tilted away from it.

This creates a difference in the amount of solar radiation (or sunlight) that reaches different parts of the Earth and thus creates the global cycle of fluctuations that we know as the seasons.

Related advice