The Met department had earlier predicted the arrival of the monsoon rains on May 31 and said that the rains in the monsoon season that last for about four months, would be around 98 percent of the last 50-years' average.
India, on average receives about 89 centimeters of rainfall annually during the months of June to September.
Kerala, Southern parts of Tamil Nadu, Lakshadweep and the Andaman Nicobar Islands have received widespread rainfalls in the past 24 hours, and according to the Meteorological Department, this signals the arrival of the monsoon rains.
In a statement, the Indian Meterological Department said, "The onset of southwest monsoon over Kerala took place in association with an upper air cyclonic circulation over southeast Arabian Sea off Kerala coast."
It added, "Southwest monsoon has also advanced into most parts of south Arabian Sea and some parts of Tamil Nadu, south Bay of Bengal and south Andaman Sea."
The statement further added, "Conditions are favourable for further advance of southwest monsoon over some more parts of Arabian Sea, remaining parts of Kerala, some more parts of Tamil Nadu, south Bay of Bengal and Andaman Sea and some parts of Karnataka during the next 2-3 days."