The seasons change because of the tilt of the earth sometimes its facing the sun
and sometimes its not causing it to be cold in the winter and warm in the summer.
Its also based off of the amount of sunlight hitting the pole so the southern.
hemisphere is warme because it faces the sun while as up north is colder because
it is always farther away from the sun. When the earth reaches a certain tilt one part
of the world is sticking out causing that area to be warmer than others.