ICSE Class 9 Answered

Due to the rotation of the Earth on its axis which is inclined at 23 ½⁰, the heating of the continents, oceans and pressure conditions vary greatly in January and in the July season. On 21 June, when the Sun is overhead the Tropic of Cancer, the pressure belts shift 5⁰ northwards. When the Sun shines vertically over head the Tropic of Capricorn on December 22, the pressure belts shift 5⁰ south wards from their original position.  

This shifting of the pressure belts results in the seasonal climatic changes particularly between 30⁰ and 40⁰ in the Northern and the Southern Hemisphere.