What phenomenon caused the cold weather?

Hello, the main reason is the revolution of the earth.

The plane where the orbit of the earth's revolution and rotation lies has an included angle.

Causing the earth to rotate obliquely when it rotates.

When the direct sunlight point moves to the southern hemisphere,

The northern hemisphere is getting colder and colder,

When the pointing moves to the northern hemisphere,

It is getting colder and colder in the southern hemisphere.

Hope to adopt, thank you.