human
Can you tell me what causes the seasons?
assistant
The seasons are caused by the Earth’s axis tilt, which is why we have winter and summer. The Earth's axis is tilted 23.5 degrees from the vertical, which causes the Northern Hemisphere to receive more direct sunlight during summer and less during winter. This affects how much heat is retained in the atmosphere, which causes the air to expand and cool during winter, causing the formation of clouds and precipitation.