Why is it colder in the winter than in the summer? The earth's axis of rotation is tilted relative to the earth's path around the sun. As a result we are tilted towards the sun in the summer and away from the sun in the winter. Read on for a more detailed explanation.
Fact 1.	Fact 2.	Fact 3.
The earth rotates about its axis once every 24 hours. In the morning we are facing towards the sun, and at night we are facing away from the sun.	The earth rotates around the sun (approximately) every 365 days or 1 year.	The axis about which the earth rotates is tilted (by 23.5 degrees) relative to the earth's path around the sun.
Shown below are two diagrams of the earth at the same time of day. On the left it is winter and on the right it is summer (in the northern hemisphere). Notice that the same spot (red circle) in the winter receives much less light than in the summer. As a result, it is colder in the winter than in the summer. (Note: in this diagram, the earth's axis is 33 degrees, instead of 23.5, so as to better illustrate the effect.)

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