The Science of a Farewell
The end of the monsoon isn't marked by a single date on the calendar, but by a specific set of atmospheric conditions. The India Meteorological Department (IMD) has a clear checklist before it officially announces the withdrawal. First, rainfall over
a specific region, starting with the northwest, must cease for five consecutive days. Second, an anticyclone—a large-scale circulation of winds around a high-pressure centre—must establish itself in the lower atmosphere. This feature effectively pushes the moisture-laden monsoon winds away. Finally, weather analysts look for a considerable drop in moisture levels in the air, which they verify using satellite imagery and weather balloon data. Only when all these conditions are met does the IMD declare that the monsoon has withdrawn from a particular area. It is a scientific process that unfolds over five to six weeks across the entire country.
Signs from the Sky: The 2026 Retreat
As of early September, satellite images are showing vast stretches of northwest and central India with strikingly reduced cloud cover. This is a strong indicator that the monsoon's powerful engine is beginning to weaken. Forecasters note that while rains are still active in some northern and eastern states, the conditions for a formal retreat are rapidly falling into place. Weather models predict that the official withdrawal process will likely begin from parts of northwest India after September 15. An anticyclone is expected to form and strengthen over the region, paving the way for a more organised withdrawal around September 21. This timeline aligns with the typical start date for the monsoon's exit, which normally begins from West Rajasthan around September 17.
An Erratic and Deficient Season
The 2026 monsoon season has been anything but normal. Marked by erratic behaviour, it has delivered uneven rains across the country, leading to an overall rainfall deficit of about 14% as of early September. This shortfall is largely attributed to a strong El Niño phenomenon in the Pacific Ocean, which is historically linked to weaker monsoon performance in India. Many regions have experienced prolonged dry spells followed by short, intense bursts of rain, which stressed agricultural activities even in areas where total rainfall looks healthy on paper. As the season draws to a close with below-average rainfall, the focus shifts to moisture levels in the soil, which are crucial for the upcoming winter crop planting season.
What to Expect Region-Wise
As the withdrawal line slowly moves from the northwest to the southeast, different parts of the country will experience this transition differently. For northwest India, including Rajasthan, Punjab, and Delhi-NCR, the retreat will bring clearer skies, lower humidity, and warmer, drier days first. Central India will be next, seeing a significant reduction in rainfall and a shift to a more stable, post-monsoon weather pattern. However, the story is different for the southern peninsula. For states like Tamil Nadu and coastal Andhra Pradesh, the end of the southwest monsoon doesn't mean the end of rains. The retreating winds will blow from the northeast across the Bay of Bengal, picking up moisture and bringing precipitation from October to December in what is known as the northeast monsoon. This year, however, meteorologists suggest these post-monsoon showers could be patchy or delayed.
