The India Meteorological Department (IMD) has issued its initial forecast for the upcoming southwest monsoon season (June-September), projecting below-normal rainfall across the country. The IMD anticipates approximately 80 centimeters of rain, which is 92 percent of the long-period average (LPA) of 87 centimeters, with a model error margin of +/- 5 percent.
El Niño Conditions Emerge as Key Factor
A significant contributing factor to the weaker monsoon outlook is the expected emergence of El Niño conditions around June, following a three-year hiatus. El Niño, characterized by a warming of the equatorial Pacific Ocean, is historically associated with diminished monsoon winds and drier weather patterns over India. The last such event occurred in 2023, with earlier instances noted in 2015, 2009, and 2002.
Currently, weak La Niña conditions are transitioning into ENSO-neutral conditions in the equatorial Pacific. La Niña typically exerts a temporary cooling influence on global temperatures.
Other Climatic Influences and Regional Outlook
While El Niño presents a challenge, climate models also suggest the potential development of positive Indian Ocean Dipole (IOD) conditions during the latter half of the monsoon season. A positive IOD is generally linked to increased rainfall and could help mitigate some of the adverse effects of El Niño in the later stages of the monsoon, according to IMD Director General M Mohapatra.
The IMD also observed slightly below-normal snow cover in the Northern Hemisphere between January and March, a factor that has an inverse relationship with India’s monsoon rainfall.
Regionally, below-normal rainfall is expected across most parts of the country. However, some areas, including segments of the Northeast, Northwest, and South Peninsular India, may experience normal to above-normal precipitation.
Why a Weak Monsoon Matters for India
The southwest monsoon is vital to India, delivering approximately 75 percent of the nation's annual rainfall. Its performance is critical for numerous sectors, including irrigation for agriculture, replenishment of drinking water sources, and hydropower generation. With nearly 64 percent of India's population relying on agriculture, and only about 55 percent of the net cultivated area being irrigated, monsoon rains are indispensable for the livelihoods of millions.
Private weather forecaster Skymet Weather has independently corroborated the IMD's outlook, also projecting below-normal rainfall at 94 percent of its long-period average (868.6 mm) for the four-month period. Skymet similarly attributes the anticipated reduction in precipitation during the second half of the season to the El Niño weather pattern.