Southwest Monsoon season is not considered rainiest for the state. Being in the rain shadow area during the season, Tamil Nadu receives mere 35% of annual rainfall during 4 month long southwest monsoon(June-Sep). The state, on an average receives 336mm of rainfall against its annual quota of 939mm. Nearly 50% of yearly rainfall is witnessed during the three month long Northeast Monsoon season, from October to December.
Southwest Monsoon 2022 has been the rainiest on record since the start of this century. Between 2005 and 2021, the state received large surplus of 31% in 2017 and a massive shortfall of 23% in 2012. The state witnessed good monsoon even when Pan-India suffered monsoon drought in 2009 and 2014. However, the state has experienced 3rd successive good southwest monsoon, with 2022 likely to be the best of all.
Southwest Monsoon Rainfall (%) : 2005-2022
Southwest monsoon starts retreating from the western parts anytime after 15thSep. There could be some delay this season. However, monsoon rains continue over South Peninsula, including Tamil Nadu during September. Factually, these rains continue even in October and swap with Northeast Monsoon sometime around 20thOctober. There is no major downpour expected over the state of Tamil Nadu during the remaining days of September. Light rains, interspersed with few moderate wet spells are likely, mostly along the coastline.
