The phenomenon that leads to the variation in temperature experienced in different seasons is primarily caused by the tilt of the Earth's axis and its orbit around the Sun. As Earth revolves, different regions receive varying amounts of sunlight throughout the year due to this axial tilt. This results in seasonal changes in temperature, with summer occurring when an area is tilted toward the Sun, while winter happens when it is tilted away. This axial tilt creates the seasonal cycle experienced in various climates around the globe.