Earths rotates on its axis that is tilted at 23.5° and is reconcile for different seasons on the planet. But the tilt in earth has not been the same since the formation of the planet that is about 4.5 billion years ago.
As the earth continued to evolve the Milankovitch cycle that is a cycle of f 40,000 years causes the planet to change its tilt. The tilt in the earth's axis varies from 22.5 to 24.5° and has done so in its geologic time.
