Seasons occur due to the tilt of Earth's axis, which is about 23.5 degrees relative to its orbital plane.
This tilt causes different parts of the Earth to receive varying amounts of sunlight throughout the year.
When one hemisphere is tilted towards the Sun, it experiences summer because the Sun's rays strike it more directly.
At the same time, the other hemisphere is tilted away and experiences winter because the Sun's rays are spread out over a larger area, making the days shorter and colder.
The Earth's distance from the Sun does not significantly affect the seasons, as the Earth's orbit is nearly circular, meaning the change in distance is minimal.
Similarly, the Earth's revolution around the Sun affects the timing of the seasons, but it is the axial tilt that is the primary cause.