New Delhi (PTI): The south-west monsoon, a lifeline of millions of farmers of the country, is expected to hit the Kerala coast on May 29, four days ahead of its normal onset.

With the strengthening and deepening of monsoon winds and widespread rainfall activity, the southwest monsoon advanced into southeast Bay of Bengal, Andaman Nicobar Islands and north Andaman sea two days back, the India Meteorological Department (IMD) said on wednesday.

"The onset forecast model suggests that the monsoon onset over Kerala is likely to be on May 29 with an error margin of four days," the weather office said.

The normal onset for monsoon over Kerala is June 1.

The Andaman archipelago has been receiving monsoon rains for the past few days and the IMD had announced the annual seasonal rains had set in over the Andaman Seas on May 10.

Since 2005, IMD has been issuing operational forecasts for monsoon onset over Kerala using statistical techniques.

Over the past 11 years, monsoon has set in over Kerala in advance on four occasions, the earliest being in 1999 when the it received rains on May 22 against the forecast for May 26.

Monsoon had been delayed by 13 days in Kerala in 2003 when the weather office had forecast the onset to happen on June seven.

In 1997, monsoon had reached Kerala on June 12 against the forecast date of June 10, in 1998 the onset was on June three while the model predicted it to be June eight, 1999 -- May 22 (forecast date May 26), 2000 -- June one (May 27), 2001 -- May 26 (May 27), 2002 -- June nine (June four), 2003 -- June 13 (June seven), 2004 -- June three (June seven), 2005 -- June seven (June 11), 2006 -- May 26 (May 30) and 2007 -- May 28 (May 24).