The Met Department on Friday forecast that the southwest monsoon would hit the Kerala coast on May 29, three days before its normal onset date.
The India Meteorological Department said conditions were favourable for the onset of monsoon over the Andaman Sea and southeast Bay of Bengal from May 23.
"The southwest monsoon is expected to set over Kerala on May 29 with a modelled error of plus or minus four days," the IMD said.
The normal onset date for the monsoon to hit Kerala is June 1. The event marks the start of the rainy season over the region and as the monsoon progresses northward, relief from scorching summer temperatures is experienced over the areas.
In its first stage long-range forecast for the 2018 southwest monsoon seasonal rainfall released last month, the IMD had predicted that the country was expected to receive 97 per cent rainfall of the Lomng Period Average (LPA).
The monsoon is considered normal if the average rainfall is between 96 to 104 per cent of long period average. Anything less than 90 per cent of LPA is termed a 'deficient' monsoon, and 90-96 per cent of the same is considered 'below normal'.
Last week, Skymet, a private weather forecasting agency had predicted that the southwest monsoon would hit the Kerala coast on May 28.
Last year, monsoon had hit Kerela on May 30, two days ahead of its normal onset date.