The onset, advance and progress of the South West Monsoon is a treat to watch and fills one with joy and excitement; especially in south Asia.
The best country to observe the progress and advance of the monsoon is India. Here, since the days of the Raj, monsoon onset days of each station are clearly defined. For instance, as far as mainland India is concerned, Kerala coast is the first to get the rains on June 1. Goa gets hit about June 5 and by the 10th of June monsoon rains must be expected in Mumbai. Kolkata has more or less the same date as that of Mumbai. Then the monsoon starts its westward march.
The area from Patna in Behar to Ahmedabad in Gujrat is covered between 10th and 15th of June. It includes famous central and South Central cities of Bhopal and Nagpur respectively. New Delhi gets its first shower by the 25th of June and by 1st July area up to Amritsar, in Punjab is covered by the South West Monsoon. West Rajasthan is the last to receive monsoon rain and typically no rain is received until the middle of July.
In Pakistan, Lahore is one of the first stations to be hit by monsoon in the first week of July. Then comes the turn of the piedmont plains and Islamabad. Peshawar does not get any rain of importance and the monsoon normally does not cross Attock.
In the south, Karachi has but a little rain by the second week of July but westwards to this station, little or no rain is received and the complete Province of Baluchistan is out of pale of a monsoon.
Having said this, if we return to India then the Andaman Islands are the first to get rains from the South west Monsoon. Here the date of onset of monsoon is May 15th. The rain is more in intensity and duration than that of mainland India; Cherrapunji in Meghalaya being an exception.
The most sort after place, however, is the tip of Kerala coast where hotels are reserved for observing the first monsoon rain. People from all over the world come to this coast and wait impatiently with full of excitement for the thick dark clouds of a monsoon accompanied with cool pleasant wind to arrive.
In short, the arrival of a monsoon is a treat to watch especially in India where common people are tired of the excessive heat of the Pre-monsoon months.