The Indian monsoon, long considered a stable feature of the subcontinent’s climate, is undergoing major changes due to climate change. While overall annual rainfall has not shown a consistent trend at the national level, significant regional shifts and rising extremes are now evident.
Dr. Rajeevan Madhavan Nair, former Secretary at the Ministry of Earth Sciences, highlighted growing disparities in monsoon behaviour. States like Kerala, parts of Northeast India, and East Central India are experiencing declining seasonal rainfall, while areas such as North Karnataka, Maharashtra, and Rajasthan are witnessing an increase. More alarmingly, extreme rainfall events—those exceeding 150 mm in a day—have increased by 75% in central India between 1950 and 2015.
Alongside this, dry spells are also becoming more frequent and prolonged. Between 1981 and 2011, dry spells during the summer monsoon season increased by 27% compared to the period from 1951 to 1980. The number of years with deficient rainfall and the extent of drought-prone areas are also on the rise.
These shifts pose serious risks for Indian agriculture. The rainfall is increasingly concentrated in short, intense bursts—nearly half of the seasonal total now falls within just 20 to 30 hours—leaving long dry gaps that affect soil moisture, crop growth, and water availability.
In addition, the traditional rhythm of the monsoon is changing. July, once the peak rainfall month, is showing a decline, while September is becoming wetter. The onset and withdrawal of the monsoon are also shifting across regions, further complicating farming calendars and water management efforts.
Natural climate drivers like the Inter-Tropical Convergence Zone (ITCZ), El Niño, and La Niña remain key influences. The ITCZ, a low-pressure zone near the Equator, guides the seasonal flow of moist winds toward India, acting like a monsoon switch. El Niño events, marked by warming in the Pacific Ocean, often weaken the monsoon, while La Niña tends to strengthen it. Out of 16 El Niño years since 1950, seven have caused below-normal rainfall in India.
Despite these disruptions, recent years have seen some positive trends. In 2024, India recorded 108% of its Long Period Average (LPA) rainfall during the June–September southwest monsoon season. That year, 78% of districts received normal to excess rainfall—the highest in over a decade. However, East and Northeast India continued to face deficits.
Experts emphasize the need for robust forecasting and climate-adaptive strategies to manage the growing variability. As the monsoon becomes more erratic, safeguarding agriculture, water resources, and disaster preparedness will be crucial for the country’s future.