India is bracing for a potentially dry post-monsoon season, with a strengthening El Niño phenomenon expected to be the dominant climate driver. The India Meteorological Department (IMD) indicates that strong El Niño conditions are currently active over the equatorial Pacific Ocean, with sea surface temperatures significantly above normal. Forecasts suggest this pattern will intensify through the end of 2026.
El Niño's Influence and the Indian Ocean Dipole
El Niño, characterized by warmer-than-average sea surface temperatures in the central and eastern equatorial Pacific, significantly alters global atmospheric circulation. This can lead to varied weather impacts worldwide, including reduced rainfall in parts of India. The IMD's Monsoon Mission Coupled Forecast System (MMCFS), alongside other global models, predicts El Niño's continued strengthening.
Adding to the concern, the Indian Ocean Dipole (IOD) is projected to remain in a neutral phase during the crucial northeast monsoon season. The IOD is another climate phenomenon driven by sea surface temperature differences between the western and eastern tropical Indian Ocean. A positive IOD, marked by warmer waters near Africa and cooler waters near Indonesia, typically supports rainfall over the Indian subcontinent.
However, with a neutral IOD, there will be no significant temperature contrast across the Indian Ocean to provide a rainfall-supporting influence. This means the neutral IOD is unlikely to counteract the drying effects of El Niño, leaving the Pacific climate pattern as the primary signal affecting India's weather in the coming months.
Post-Monsoon Rainfall Outlook and Regional Impacts
The October-December period is particularly vital for southern peninsular India, as the northeast monsoon contributes a substantial portion of its annual rainfall. States such as Tamil Nadu, Puducherry, and parts of Andhra Pradesh, Kerala, and Karnataka are highly dependent on this season for their water resources and agricultural needs.
While El Niño's impact is generally associated with reduced rainfall, its effects are not uniform across the entire country. Regional variations are expected, meaning some areas might still receive normal or even above-normal rainfall despite the broader climate pattern. However, the IMD's assessment points to El Niño remaining the dominant influence throughout the post-monsoon period.
This outlook follows a southwest monsoon season that concluded with rainfall approximately 13 percent below normal, delivering only about 87 percent of the long-period average. This makes it one of the weaker monsoon seasons in recent years, further emphasizing the importance of the upcoming post-monsoon period for agriculture and water management.
“With El Niño strengthening and no positive IOD expected to develop, the Indian Ocean is unlikely to provide a significant counter-effect to the Pacific warming pattern,” stated the IMD.
The coming months will be critical for the southern states reliant on northeast monsoon rainfall, as well as for overall agricultural output and water security in regions already impacted by the deficient southwest monsoon.