Over a week past the monsoon’s normal arrival date, the rain clouds have yet to reach Mumbai, driving India’s nationwide monsoon deficit to 35% on June 16. The shortfall in rainfall is concentrated in the regions the monsoon has failed to cover — Maharashtra, the Konkan coast, and the adjoining regions of central India — where its northward progress has been stalled for several days.

India Meteorological Department (IMD) statistics show that, apart from northwest India, which has received 5% more rain than normal for this time of the year, all other regions are in the red, including east and northeast India (43%), central India (63%), and the southern peninsula (14%).

Super El Niño year

While a rainfall deficit in June, the first of the monsoon months, is not unusual, it assumes additional significance in a year that forecasters globally have warned will likely be a ‘Super El Niño’ year.

Also Read: Why is the El Niño so hard to predict?

An analysis of the IMD’s all-India June rainfall departures for El Niño years since 2000 shows no consistent early-season signal. In June 2015, during one of the strongest El Niño events on record, rainfall was 14% above normal. June 2002 and June 2004, both years that ended in drought, recorded near-normal June rainfall of around 2% and 1% above normal, respectively, with the deficits arriving only in July and later.

Only in 2009 (47% below normal) and 2014 (44% below normal) did June rainfall fail as sharply as it has this year. In 2023, the most recent El Niño year, June closed about 8% below normal, within the IMD’s normal range.

An El Niño event — the periodic warming of the central and eastern Pacific Ocean that tends to suppress the Indian monsoon — establishes itself only in the spring and exerts its influence mainly in the middle and later part of the season. “June rainfall and the pace of onset, by contrast, are governed largely by local and regional factors,” according to D.S. Pai, chief forecaster at the IMD’s Regional Meteorological Centre in Chennai.

First pulse lost momentum

This year, the monsoon set in over Kerala on June 4, just three days behind its normal date, but its advance up the west coast has since lost momentum. Dr. Pai explained that the monsoon moves in pulses, and the first pulse, having reached the outskirts of Mumbai, did not sustain itself. Instead, an “anticyclonic circulation” to the city’s north, combined with a westerly push from mid-latitude weather systems, has prevented the monsoon from establishing itself, he told The Hindu.

The Madden-Julian Oscillation, a travelling band of atmospheric activity that can strengthen or weaken the monsoon, is currently in an “unfavourable phase”. This implies that the onset over Mumbai is likely to be delayed by a further five to six days, until the next pulse strengthens, possibly aided by a low-pressure system forming over the Bay of Bengal, he reckoned.

Dire warnings

The U.S. National Oceanic and Atmospheric Administration issued an El Niño advisory on June 11, confirming the event had formed and placing the odds of it becoming “very strong” by winter at 63%. The World Meteorological Organization had earlier put the probability of El Niño emerging between June and August at 80%. The IMD’s own June bulletin states that El Niño conditions are present and that the ocean and atmosphere have coupled, with no positive Indian Ocean Dipole expected to offset it this season.

The warnings have been building. IMD’s first-stage forecast in April pegged seasonal rainfall at 92% of the long-period average; its May-end update lowered this to 90% and assigned a 60% probability to a deficient year — the agency’s most pessimistic pre-season call since 2015.

Farm impact

Chairing a review of kharif preparations on June 16, Union Agriculture Minister Shivraj Singh Chouhan directed States to identify districts facing low or uneven rainfall and to draw up crop-wise contingency plans, so that affected farmers could be “immediately provided with alternatives, advice, and assistance.”

The Centre has placed 150 to 200 districts under priority monitoring, ordered weekly El Niño reviews, and is encouraging a shift towards cotton and pulses. Mr. Chouhan has maintained that seed and fertiliser stocks are adequate and that reservoir storage — at 30.4% of capacity in May, against a 25.1% average in previous El Niño years — leaves India better placed than in earlier deficient seasons.

Analysts are more cautious: the rating agency ICRA has estimated that a serious farm disruption could add about 0.4 percentage points to retail food inflation, a risk the Reserve Bank of India has flagged. 

One likely fallout of El Niño conditions is the tightening of an already stressed fertiliser supply, with India contending with China’s curbs on di-ammonium phosphate exports, and elevated natural gas prices feeding into the cost of domestic urea production as well.

Monsoon vs westerlies

The monsoon’s sluggishness also reflects a tug-of-war between the monsoon and mid-latitude weather systems, Dr. Pai said. The mid-latitudes are the zone between the tropics and the poles, dominated by eastward-flowing westerly winds; western disturbances — rain-bearing storms that arrive from the Mediterranean and West Asia and usually affect northwest India in winter — are embedded in that flow.

“Whichever system is stronger controls the Indian region. In summer, a vigorous monsoon normally pushes the westerlies northward; in winter, the westerlies dominate and the monsoon retreats to the southern hemisphere. June is a transition between the two. Because El Niño has weakened the monsoon, it has so far been unable to push the mid-latitude systems back, allowing them to intrude further south and stall its advance,” Dr. Pai said. A strong monsoon, by contrast, can interact with an incoming western disturbance to its advantage — the two systems effectively hand-holding to deliver heavier rain over north and northwest India — whereas a weak monsoon is simply pushed back.