Monsoon is likely to hit the southern Kerala coast on May 30, two days before its scheduled arrival in India, the weather office said on Thursday.
But, the country stares at the possibility of below normal rains for a second consecutive year at a time farmers are worried about dry weather from an El Nino weather pattern this year.
The Indian Meteorological Department (IMD) said conditions were becoming "favourable" for advancement of southwest monsoon over the Andaman Sea and adjoining areas during the next 3-4 days.
"The southwest monsoon is likely to set over Kerala on May 30 with a model error of ± 4 days," IMD said in a statement.
The June-September monsoon season is vital for the country as half its croplands lack irrigation, but a forecast of less rain than usual due to the emergence of the El Nino has threatened to worsen rural distress.
For millions of farmers whose winter-sown crops were damaged by unseasonal rains in February and March, the IMD prediction of a timely start to the monsoon may help them plan their sowing better.
IMD considers a June 1 arrival as normal. Last year the annual rains hit the Kerala coast on June 6, leading to deficient rains that trimmed grain output.
"A timely onset of monsoon will help ease threats of El Nino from the minds of farmers to some extent," said Sudhir Panwar, chief of farmers' lobby group Kisan Jagriti Manch. "This could also lead to timely sowing of summer crops."
The El Nino, or a warming of sea-surface temperatures in the Pacific, brought the worst drought in four decades to India in 2009. A repeat could severely hit farming, which accounts for 15% of the country's $2 trillion (almost Rs 127 lakh crore) economy and supports two-thirds of its 1.25 billion population.
Any surge in food prices could fuel inflation and dent Prime Minister Narendra Modi's popularity in the countryside.
"There are instances in the past when the monsoon onset took place much ahead of the normal date but the season turned out to be dry as happened in 2009," IMD's chief forecaster DS Pai said.