Retreating Monsoon

The northeast monsoon has arrived in Tamil Nadu and Puducherry, bringing heavy rainfall, particularly to the northern regions of the state, including Chennai and its surrounding districts.

North East/Retreating Monsoon

It refers to the withdrawal of the southwest monsoon from India, starting in early October and lasting until November.
During this phase, the wind pattern reverses, moving from the land towards the sea as the low-pressure zone over the northern plains weakens and a high-pressure zone develops.

Phenomena Behind Retreating Monsoon

Weakened Low Pressure: As the land cools faster than the ocean in autumn, the low-pressure system that brought monsoon rains to the Indian subcontinent weakens.
Change in Wind Direction: The winds shift from southwesterly to northeasterly as they blow from the high-pressure areas over the land to the low-pressure areas over the sea.
Reduced Rainfall: Rainfall gradually decreases as moisture-laden winds retreat, but the coastal regions still receive showers, often in the form of cyclones.

States Benefiting from Retreating Monsoon:

Tamil Nadu: It receives significant rainfall during this period, unlike during the southwest monsoon.
Andhra Pradesh: Coastal areas benefit from occasional rains.
Karnataka and Kerala: Some parts, especially coastal regions, receive rainfall during the retreat.

Difference between South West Monsoon & NorthEast Monsoon

Feature	South West Monsoon	NorthEast Monsoon
Duration	June to September	October to December
Rainfall Contribution	About 75% of annual rainfall in India	Approximately 11% of annual rainfall in India
Geographical Impact	Affects most of India, especially the western and central regions	Primarily impacts Tamil Nadu, coastal Andhra Pradesh, and Rayalaseema
Wind Direction	Winds from the southwest (Arabian Sea)	Winds from the northeast (Bay of Bengal)
Temperature Changes	Sudden drop in temperature; high humidity	Less dramatic temperature changes; cooler conditions can prevail
Agricultural Impact	Critical for kharif crops like rice and cotton	Important for rabi crops, particularly rice and maize in the southeastern states
Variability	More consistent rainfall patterns	Highly variable; can lead to droughts or floods depending on the year