Monsoon is on track to arrive near the normal date of June 1 over the southern coast, give or take two days, a meteorological expert and former government forecaster said on Friday.
The four-month long rainy season starts over the Kerala coast and covers the rest of India and neighbouring countries by mid-July.
"The monsoon rains are expected to hit the Kerala coast close to its normal date of arrival," said PV Joseph, a former director at the India Meteorological Department and now professor emeritus in the atmospheric science department at Cochin University of Science and Technology.
Joseph bases his forecast on the "pre-monsoon rain peak," when the temperature of the Bay of Bengal off the east coast of the subcontinent rises about 40 days before the monsoon and clouds near the equator move north.
This peak was visible during April 21-26, he added.
Joseph, who is often consulted by the government's weather office, said there was around four days' degree of variance in the forecast.
"This year monsoon could arrive over the southern coast at least two days before or after the normal date," he said.
The Indian weather office treats June 1 as the normal date for the monsoon arrival over the southern coast based on a time series rainfall data of over 100 years.
Last month, India's weather office forecast normal rains for the second straight year in . That could mean output of key crops like rice and sugar once again exceeds demand, providing some relief as Asia's third-largest economy battles inflation.
"If any cyclone develops in coming days than the onset could be delayed," Joseph said.
Last year, he forecast arrival of the monsoon would be 7-10 days ahead of over the Kerala coast, but a cyclone in mid-May on the east coast brought the seasonal rains on May 31, a day ahead of the normal date.
The monsoon hit a week ahead of normal in 2009 but the season turned out to be the driest in four decades, causing widespread losses to key crops such as oilseeds and sugarcane, pushing up food inflation.