Observing the Sky: Motion of the Earth - Seasons

If you live near the equator, you don't experience winter, spring, summer, and fall. But farther to the north and south, you notice a change in the seasons. The seasons can be different lengths and temperatures depending on where you are. In some places, winter is very cold with lots of snow and ice. In other places, winter is not much cooler than summer and it is not cold enough for snow. In the regions midway between the equator and the poles, the seasons do change and each lasts about 3 months.

The changing seasons are caused by the tilt of the Earth and its orbit around the Sun. When one hemisphere leans more toward the Sun, it receives more direct sunlight while the other hemisphere receives more indirect sunlight. Direct sunlight brings more of the Sun's energy to a given area so people can spend more time outside without bundling up. If the Earth did not orbit the Sun, the amount of direct or indirect light each area receives would never change and we would all be stuck in the same seasons forever.