Summer starts in the month of April in India, so the temperature starts rising and atmospheric pressure starts falling in the regions of Northern India during this period. During this period, the plains of Upper Ganga, West Rajasthan, West Punjab and West Kashmir become the centers of low atmospheric pressure.
On the other hand, due to low temperature, high atmospheric pressure is found in Lakshadweep islands group, Arabian Sea and Andaman Nicobar islands group. In the month of October, atmospheric conditions are inversed, as the sun starts to move to southern direction, and due to low temperature, high atmospheric pressure is found in northern India, Rajasthan, west Punjab and Haryana, while in the southern central part, there is low pressure due to high temperature.
