India's monsoon onset over the southernmost Kerala coast is delayed by another two-three days because the formation of cyclonic circulation in the Arabian Sea has reduced cloud cover over the Kerala coast, weather officials said on Monday.

The monsoon, the lifeblood of the country's $3 trillion economy, delivers nearly 70% of the rain India needs to water farms and recharge reservoirs and aquifers.

The state-run India Meteorological Department (IMD) was expecting the arrival of monsoon rains over the Kerala coast on June 4, the latest arrival in four years.

"The development of cyclonic circulation over the southeast Arabian Sea has been pulling moisture out of Kerala coast," said a senior IMD official, who declined to be named as he is not authorised to talk to media.

The monsoon could arrive in the next two-three days, the official said, offering relief to farmers keenly waiting for the start of the wet season which is crucial for summer crops.

Nearly half of India's farmland, without any irrigation cover, depends on the annual June-September rains to grow several crops.

The monsoon's late start could delay the planting of rice, cotton, corn, soybean and sugar cane.

The monsoon should pick up momentum and cover the entire country on time, said another official who declined to be named.

"Let's hope it will move quickly once it sets over Kerala," he said.

India's weather office has forecast below average rains for June, with the monsoon expected to pick up in July, August and September.

However, for the entire four-month season, the IMD has forecast an average amount of rain despite the formation of a possible El Nino weather phenomenon.

A strong El Nino, marked by a warming of the sea surface on the Pacific Ocean, can cause severe drought in Southeast Asia, India and Australia while drenching other parts of the world such as the U.S. Midwest and Brazil with rain.

The emergence of a strong El Nino triggered back-to-back droughts in 2014 and 2015 for only the fourth time in over a century, driving some Indian farmers into extreme poverty. (Reporting by Rajendra Jadhav, editing by Ed Osmond)