Seasons of India - Northeast monsoon season or Retreating Monsoon

• Trough: An elongated area of relatively low pressure extending from the center of a region of low pressure.
• Stalactite: A stalactite is an icicle-shaped formation that hangs from the ceiling of a cave. 
• Stalagmite: A column of rock that rises from the floor of a cave, formed over a very long period of time by drops of water containing lime falling from the roof of the cave. 
• Coriolis force: The invisible force that appears to deflect the wind is the Coriolis force.

Northeast monsoon season or Retreating Monsoon

• The South-West Monsoon starts retreating from northern India in early October. Hence, the months of October and November are known for the retreating monsoon. 
• The southwest monsoon wind returns from Indian landmass and blows towards Bay of Bengal. The coriolis force deflects this wind and makes it to blow from northeast. Hence, it is known as Northeast monsoon or Post-monsoon season.  
• The monsoon trough or low-pressure trough over the northern plains weakens during October-November as the sun appears to move southward. A high-pressure system gradually replaces this. The south-west monsoon winds begin to weaken and withdraw gradually. The monsoon has left the Northern Plains by the beginning of October.
• The months of October-November form a period of transition from hot rainy season to dry winter conditions. The withdrawal of the monsoon season is marked by clear skies and a rise in temperature. While the daytime temperatures are high, the nights are cool and pleasant. The land is still wet.
• The combination of high temperature and humidity gives rise to an oppressive weather. This is commonly known as 'October heat'.
• Northern India's temperatures begin to fall rapidly in the second half of October. By early November, the low-pressure conditions over northwestern India has been transferred to the Bay of Bengal. This shift is linked to the occurrence of cyclonic depressions that originate over the Andaman Sea.
• These cyclones usually cross the eastern coasts of India, causing heavy and widespread rain. These tropical cyclones are often very destructive. Cyclones frequently strike the densely populated deltas of the Godavari, Krishna, and Kaveri, causing significant damage to life and property. These cyclones occasionally arrive at the coasts of Odisha, West Bengal, and Bangladesh. The majority of the Coromandel Coast's rainfall is caused by depressions and cyclones.
• Rainfall in Andhra Pradesh, Tamil Nadu, Kerala, and south interior Karnataka accounts for 35% of the annual total.