Retreating monsoon is a meteorological phenomenon that occurs in India and is characterized by the withdrawal of the southwest monsoon winds from the skies of North India during the months of October and November. It is also known as the Northeast Monsoon or Post-Monsoon Season. The retreating monsoon season commences with the beginning of the withdrawal of the southwest monsoon from mid-September to November and lasts till early January. During this time, the Indian subcontinent starts to witness a sudden change in weather, and the climate becomes drier and colder. The withdrawal of the retreating monsoon is gradual and takes a longer duration compared to the advancing one.

The retreating monsoon brings rainfall in an unevenly distributed manner over India, with some locations receiving a lot of rainfall and others receiving very little. The southeastern coast of India, particularly Tamil Nadu, receives almost half of its annual rainfall during this time, which is called the northeast or winter monsoon. Severe tropical cyclones emerge from the Bay of Bengal during the retreating monsoon, and the month of October-November is prone to severe cyclones.

The retreating monsoon is important to Indian agriculture, and the substantial year-to-year variability of rainfall, in both timing and quantity, introduces much uncertainty in the country’s crop yield. Good years bring bumper crops, but years of poor rain may result in total crop failure over large areas, especially where irrigation is lacking.