"Conditions are becoming favourable for advance of southwest monsoon over Andaman Sea and adjoining southeast Bay of Bengal during next 3-4 days," the weather office announced late this evening.
The seasonal rains then make steady progress towards the mainland, bringing showers to the Kerala coast first and cheer to millions of farmers.
Last week, the weather office had announced that Kerala would receive its first monsoon rains by June 1.
In April, India had predicted a normal monsoon for the third consecutive year.
There was 47 per cent probability of a normal monsoon as against 24 per cent probability of below normal rains this season, the weather office said in the long range forecast announced on April 26.
Monsoon is crucial for kharif crops such as rice, cotton, soyabean and maize because almost 60 per cent of the farm land in the country is rainfed.
India is estimated to have harvested a record 252.56 million tonnes of foodgrains in the 2011-12 crop year as against 244.78 million tonnes in the previous year.