What is the primary cause of the seasons on Earth?

The primary cause of the seasons on Earth is the tilt of the Earth's axis. The Earth is tilted at an angle of approximately 23.5 degrees relative to its orbital plane around the sun. This axial tilt is responsible for the variation in sunlight that different parts of the planet receive throughout the year.

As the Earth orbits the sun, different regions are exposed to varying intensities of sunlight, leading to seasonal changes. For example, during the summer solstice in the Northern Hemisphere, the North Pole is tilted toward the sun, resulting in longer daylight hours and warmer temperatures. Conversely, during the winter solstice, the North Pole is tilted away from the sun, leading to shorter days and colder temperatures.

While the distance from the sun, the Earth's rotation speed, and the elliptical shape of its orbit can influence climatic conditions, they do not directly cause the seasons. The axial tilt remains the fundamental reason behind the cyclical changes in weather and daylight that we experience as seasons.