What Exactly is Monsoon Withdrawal?
Think of the monsoon as a massive sea breeze that blows from the southwest, carrying moisture from the Indian Ocean over the subcontinent. Its withdrawal is simply the reversal of this process. The India Meteorological Department (IMD) officially declares
the withdrawal based on a strict set of criteria observed over a region. These include a halt in rainfall for five consecutive days, a significant drop in atmospheric moisture, and the establishment of a high-pressure system, known as an anticyclone, in the lower atmosphere. This anticyclone effectively pushes the moist, rain-bearing winds away, allowing drier, continental air to take over.
The Timeline: When is it Happening?
While satellite images are showing clearer skies over parts of the country, the official withdrawal has not yet begun as of early September. According to forecasters, the conditions for this grand retreat will likely become favourable after September 15. The process traditionally starts in the extreme northwestern parts of India, primarily over West Rajasthan, and then gradually backs out across the rest of the country over several weeks. Weather models predict that the crucial anticyclone needed for the withdrawal will strengthen over northwest India, possibly maturing around September 21, which would set the stage for a more organised retreat.
Clear Skies for the North, Winter is Coming
For North and Central India, the withdrawal is the definitive end of the rainy season. The reversal of winds will bring in drier northwesterly air, leading to a significant reduction in humidity and mostly clear skies. While this initially causes a brief spell of hotter daytime temperatures due to the direct sun, it is the primary trigger for the onset of autumn and, eventually, winter. The cool, crisp mornings that mark the festive season in the northern plains are a direct consequence of this large-scale atmospheric shift.
A Different Story for the South
The end of the southwest monsoon does not mean the end of rains for everyone. For India's southeastern coast, it marks the beginning of their main rainy season. As the southwest monsoon retreats, the wind patterns reverse to a northeasterly flow. These winds pick up moisture from the Bay of Bengal and deliver what is known as the Northeast Monsoon. This 'retreating monsoon' is critical for states like Tamil Nadu, Rayalaseema in Andhra Pradesh, and parts of Kerala, providing them with a significant portion of their annual rainfall between October and December. However, this year's strong El Niño has led to predictions that the northeast monsoon could be delayed or patchy.
The Cyclone Season Factor
The post-monsoon period of October and November is also the peak season for cyclone formation in the North Indian Ocean, especially in the Bay of Bengal and the Arabian Sea. The withdrawal of the monsoon trough—a large area of low pressure—leaves a void. The sea surface temperatures are still warm, providing the perfect fuel for tropical storms to intensify into cyclones. While the southwest monsoon's presence often suppresses the formation of major cyclones, its departure opens the door for these powerful and potentially destructive weather systems to develop, posing a seasonal threat to India's extensive coastline.
Impact on Agriculture and Water
The timing and performance of the monsoon's withdrawal have massive implications for agriculture. An erratic 2026 monsoon, which has already resulted in a nationwide rainfall deficit, has not fully replenished reservoirs and groundwater levels. This has raised concerns about water availability for the upcoming Rabi (winter) crop season, which depends heavily on irrigation for crops like wheat, mustard, and chickpeas. A timely withdrawal with a final spell of rain is often beneficial, but this year’s deficit could mean tighter water supplies for farmers heading into 2027.
