The Science of Withdrawal
The monsoon doesn't just switch off; it retreats. This withdrawal is a gradual process that typically begins in the northwestern parts of the country around the middle of September. The India Meteorological Department (IMD) officially declares the withdrawal when
specific conditions are met: a cessation of rainfall for five consecutive days, the establishment of an anticyclone (a high-pressure system) in the lower atmosphere, and a significant drop in moisture. This process moves southeast across the country over several weeks, meaning that while Rajasthan may be drying out, southern states like Kerala could still be experiencing monsoon rains. It's a staggered, weeks-long event, not a single national occurrence.
The Forecast for This September
Recent forecasts for September 2026 suggest a complex picture. While the formal withdrawal from the northwest is expected to begin after September 15, several regions are seeing active rainfall in the first half of the month. A low-pressure area over central and northern India is bringing fairly widespread rain to states like Uttar Pradesh, Uttarakhand, and Madhya Pradesh. At the same time, forecasts indicate that overall rainfall for September might be below normal for the country as a whole, with above-normal temperatures expected in most parts. This points to a month of contrasts: intense wet spells in some areas, but a general trend towards warmer, drier conditions as the month progresses.
North and Northwest India: Drying Out
For North and Northwest India, including Rajasthan and the Delhi region, September is when the shift is most pronounced. These are the first areas from which the monsoon typically retreats. While early September may see some final spells of rain, conditions generally become hotter and drier as the month goes on. By late September, residents can expect clearer skies, lower humidity, and daytime temperatures that can still be quite high, often hovering in the mid-to-high 30s Celsius. It’s the start of the transition to the pleasant post-monsoon and pre-winter season.
East, Central, and Northeast: Lingering Rains
This region presents a much more varied and wet forecast for September. States like Bihar, West Bengal, Odisha, and those in the Northeast are expected to receive significant rainfall, with heavy showers predicted through mid-September. The same applies to central India, where states like Madhya Pradesh and Chhattisgarh are also on track for continued wet weather. For households here, the monsoon is far from over. It's crucial to remain prepared for heavy downpours and potential waterlogging. These regions are often among the last to see the monsoon withdraw completely.
The Southern Peninsula: A Tale of Two Coasts
In the south, the weather is more complex. The southwest monsoon's withdrawal from states like Kerala and coastal Karnataka is gradual, with rainfall often continuing through September and even into October. This year, Kerala is forecast to see widespread rain in the second week of September. Meanwhile, the southeastern coast, particularly Tamil Nadu, enters a brief lull before its main rainy season—the Northeast Monsoon—begins later in October. While September can be relatively drier here, humidity remains high, and temperatures on both coasts stay warm, typically between 26°C and 34°C.
How Your Household Can Adapt
Preparing for this transitional weather is key. With humidity still high, it's important to prevent fungal growth and ensure good ventilation at home. Continue to take precautions against mosquito-borne illnesses like dengue and malaria, as stagnant water from intermittent rains creates breeding grounds. For your health, focus on light, easily digestible meals and stay hydrated. When it comes to clothing, lightweight, quick-drying fabrics are still your best bet to handle both sweat and unexpected showers. Finally, keep an umbrella or raincoat handy, as sudden showers can catch you off guard even as the season winds down.
