"The northeast monsoon rains have commenced over Tamil Nadu and adjoining areas of Kerala, south coastal Andhra Pradesh, Rayalaseema and south interior Karnataka today," the Regional Meteorological Centre (RMC) said in a statement.
Punalur (Kollam) in Kerala received 15 cm of rainfall while Mettupatti (Madurai) in Tamil Nadu recorded 8 cm of rainfall in the last 24 hours, ending at 8.30 am today, it said.
Mangaluru (Dakshina Kannada district) in Karnataka recorded 4 cm of rainfall while in Andhra Pradesh, Penagaluru (Cuddapah) registered 2 cm of rainfall, the RMC said.
The northeast monsoon brings a significant amount of rainfall to peninsular India, with Tamil Nadu dependent on it for the bulk of its annual downpour.
The southwest monsoon, which had brought copious rainfall this year in several parts of the state, including Chennai, has already withdrawn.
The India Meteorological Department has forecast that the northeast monsoon will be "most likely normal" this time, though it had been deficient last year.