Earth is tilted on an axis and spins around to give us our 24 hour days, however it also rotates around the sun to give us 365 days a year. The tilt is what shows us the 4 seasons. So take North America for example. In the winter North America is tilted away from the sun making the weather colder because we are further away from the sun. and opposite in the summer time. The weather is always warm near the equator because of its location in the middle of earth. so its distance from the sun is always lost the same.