Page 1 - Module

SAI INTERNATIONAL SCHOOL, BHUBANESWAR.

Class IX: SOCIAL STUDIES – GEOGRAPHY

CHAPTER - 4- CLIMATE
(VIRTUAL CLASSES)

MODULE No. 05

NOTES FOR CHAPTER-4- CLIMATE

1. Sub Topic- The onset of the Monsoon and Withdrawal (pg 30-31)

The Onset and Withdrawal of the Monsoon

The trade winds are steady but the monsoon winds are pulsating in nature. They are
affected by different atmospheric conditions encountered by it, on its way over the warm
tropical area. Starting from early June in the Southern part of the Indian peninsula, the
monsoon lasts between 100 and 120 days, withdrawing by mid-September.

Rainfall increases suddenly and continues for several days at the time of arrival of monsoon.
This phenomenon is called as Burst of monsoon. It is different from pre-monsoon showers.
Afterwards, it alternates with wet and dry spells.

Onset of Monsoon

Monsoon generally reaches the Southern tip of the peninsula during the first week of June.
After striking the Southern tip, it branches into two parts- the Arabian Sea branch and the
Bay of Bengal branch; both branches move rapidly.

The Arabian Sea branch advances North along the Western Ghats, reaching Mumbai by
about 10th of June and soon covers the Saurashtra-Kuchchh and central most part of the
Deccan Plateau also.

The Bay of Bengal branch reaches Assam in the first week of June and gets deflected
towards the West by the mountain ranges, thus giving rainfall to the Ganga plains.

Both the branches again merge over the North-Western part of the Ganga plains. Delhi
receives rainfall from Bay of Bengal branch by the end of June (tentative date is 29th June)
and by the first-week of July, monsoon covers Western Uttar Pradesh, Punjab, Haryana and
Eastern Rajasthan.