FactoSphere

Earth orbits around the Sun in 365.25 days. 0.25 days add to form 1 day after 4 years resulting into the leap year.

Earth completes its rotation about its axis in 23.9 days, defining days and nights.

Earth's axis of rotation is 23.5 degrees inclined from the normal to the elliptical equatorial plane of planets, giving rise to the seasons on the planet.

On two days of the year- Equinoxes, both the hemisphere is equally illuminated by the Sun.

Whichever hemisphere is close to the Sun experiences summer, while the one away from the Sun experiences winter.

The reason why India and Australia experience complete different season is due to the inclination of Earth about its axis.