Describe onset of monsoon

Onset:
(a) Generally, the monsoon arrives at the southern tip of the Indian peninsular by the first week of June. Subsequently, it divides into two branches, viz. the Arabian Sea branch and the Bay of Bengal branch.
(b) The Arabian Sea branch reaches Mumbai about ten days later, i.e. around 10th of June. The Bay of Bengal rapidly advances and reaches Assam in the first week of June.
(c) The monsoon winds are then deflected by high mountains and move towards west over the Ganga plains. The Arabian Sea branch of the monsoon arrives over Surashtra-Kuchchh and central part of the country by mid-June.
(d) The Arabian Sea and the Bay of Bengal branches of the monsoon merge over the northwestern part of the Ganga plains.
(e) Delhi usually receives monsoon showers from the Bay of Bengal branch by the end of June.
(f) Western Uttar Pradesh, Punjab, Haryana, and eastern Rajasthan experience monsoon by the first week of July. The monsoon reaches Himachal Pradesh and the rest of the country by mid-July.