A key factor causing the season is "the Sun". An important source of energy, the Earth's heat is causing a lot of processes through the atmosphere any season on the surface of the Earth has come from the West causing the effects of sunlight.
Important factors that cause the season is the "sun" of the world's major source of heat energy, causing many atmospheric processes that occur on Earth, the seasons are caused by the angle of incidence of sunlight.
The factors caused the season is "the sun." The thermal energy source of the world causing different process, the atmosphere of the various seasons occur on earth has caused from the angle of the sun.