The Great Withdrawal Begins
The four-month-long southwest monsoon season officially concludes at the end of September. The withdrawal is a gradual process that typically begins in the first week of September from the extreme northwestern parts of the country, like West Rajasthan.
The India Meteorological Department (IMD) has specific criteria for this, including a cessation of rainfall for five continuous days and the establishment of an anti-cyclone over the region. For 2026, the IMD has predicted that the withdrawal may begin on schedule around September 17. However, this year's retreat comes after a season of deficient rainfall for many areas, with August 2026 being the warmest and one of the driest since 1901. This sets the stage for a particularly warm and uncomfortable September.
The Science of 'September Heat'
The phenomenon known as 'September Heat' is a result of a frustrating combination of atmospheric conditions. As monsoon clouds clear, the sun’s rays beat down with renewed intensity, rapidly heating the land. At the same time, the ground is still saturated with moisture from the preceding months of rain. This moisture evaporates, pumping huge amounts of water vapour into the atmosphere and driving up humidity. The result is not just high temperatures, but a soaring 'real feel' or heat index. This combination of heat and high humidity is particularly taxing on the human body, as it prevents sweat from evaporating efficiently, which is our natural cooling mechanism. This makes the air feel heavy, oppressive, and often much hotter than the actual thermometer reading.
A Forecast for Discomfort
The IMD's forecast for September 2026 points towards a difficult month for much of the country. Monthly rainfall is predicted to be below normal, while average maximum temperatures are expected to be above normal for most parts of India. This is being driven by strong El Niño conditions in the Pacific Ocean, which are known to suppress monsoon rainfall and contribute to warmer temperatures in India. While August has already set records for heat, the outlook for September suggests a continuation of this trend, increasing the risk of heat stress. Agencies have been advised to prepare for the impacts, including taking measures for water conservation and agricultural planning.
Which Regions Will Be Most Affected?
The post-monsoon heat is typically felt first and most intensely in the northwestern and central parts of India, the same regions from where the monsoon first retreats. States like Rajasthan, Punjab, Haryana, Gujarat, and subsequently Madhya Pradesh and Maharashtra often bear the initial brunt of this weather shift. This year, while many parts of the country are expected to see below-normal rainfall, some areas in the northwest, northeast, and east-central India might receive normal rainfall, which could temper the heat locally. However, the general forecast remains one of above-normal temperatures across a majority of the country, making this an uncomfortable transition period for millions before the drier, cooler post-monsoon air finally establishes itself.
How to Stay Cool and Safe
Managing the September heat requires paying close attention to hydration and avoiding overexertion. With high humidity, it's easy to become dehydrated even without intense activity. It's crucial to drink plenty of water throughout the day. Opt for light, breathable clothing, preferably in light colours, to help your body stay cool. If possible, limit strenuous outdoor activities to the cooler parts of the day, such as the early morning or late evening. The combination of heat and humidity can be dangerous, leading to heat exhaustion or heatstroke, so it's important to listen to your body and seek shade or a cooler indoor environment when you feel overwhelmed. Taking cool showers can also provide temporary relief from the oppressive, sticky feeling.
