The Southwest Monsoon 2026 reached Kerala on 4 June 2026, three days later than normal and nine days after the IMD’s forecast date.
IMD has forecast below-normal rainfall at 90% of the long-period average, with a 60% chance of a deficit or deficient monsoon.
The weather agency expects El Niño conditions to develop during the monsoon season, a pattern that usually suppresses rainfall over India.
NOAA forecasts suggest the 2026 El Niño could become very strong and may persist until the Northern Hemisphere winter of 2026-27.
Neutral Indian Ocean Dipole conditions and the possible return of active western disturbances could further complicate rainfall patterns and extreme weather risks.
Monsoon 2026 has finally reached Kerala, but the bigger question is what happens next as El Niño builds over the Pacific and India faces the risk of below-normal rainfall.
The Southwest Monsoon began over the state on June 4, 2026, three days later than its normal date of 1 June and nine days later than the India Meteorological Department’s (IMD) forecast date of May 26, 2026 with several weather threats looming ahead.
The monsoon on June 4 had covered all of the state, Mahe and the Lakshadweep islands, and moved into parts of Karnataka and Tamil Nadu, IMD said in a statement. It also progressed across the Comorin area and large parts of the Arabian Sea and Bay of Bengal, including parts of the west-central, east-central and northeast Bay of Bengal.
The monsoon winds are flowing into India at a time when the global threat of an El Niño looms. Many climate scientists expect it to be a super El Niño event, rivalling the strongest El Niño on record, between 1876 and 1878. Another threat from the northwest could come in the form of continued moisture-laden western disturbances, which could bring surprises similar to those seen in 2025.
The IMD has already predicted a below-normal rainfall season at 90 per cent of the long-period average (LPA), revising its earlier estimate of 92 per cent of LPA made in April. India’s LPA for the monsoon season is 868.6 millimetres for the June-September period, based on the average monsoon rainfall between 1971 and 2020.
A season with 90 per cent of LPA would mean below-normal rainfall for the country, according to the IMD definition. The weather agency has also given a 60 per cent chance of a deficit or deficient southwest monsoon. A deficient monsoon season would mean nationwide rainfall of 89 per cent of LPA or less.
The spatial rainfall distribution map provided by the IMD also paints a grim picture, with most of the country showing chances of below-normal rainfall.
The IMD’s distribution of rainfall over the country’s homogeneous regions also showed below-normal rains, with only the northeastern region predicted to receive normal rainfall, between 96 per cent and 104 per cent of LPA.
Southwest monsoon has arrived in Andaman and Nicobar; to hit Kerala on May 26: IMD
El Niño risk
The weather agency expects El Niño conditions in the Equatorial Pacific Ocean to begin during the southwest monsoon season, with a 92 per cent chance. In El Niño years, the performance of the monsoon is generally suppressed. During the previous El Niño onset year in 2023, southwest monsoon seasonal rainfall was 94 per cent of LPA, with the northeast experiencing a deficient monsoon at 82 per cent of LPA.
In 2015, which was an onset year for a super El Niño event, the country’s monsoon seasonal rainfall was only 86 per cent of LPA. The highest deficiency was over northwest India, where rainfall was only 83 per cent of LPA.
According to a Down To Earth analysis of data from the United States National Oceanic and Atmospheric Administration, or NOAA, the El Niño of 2026 could be as strong as, or stronger than, the El Niño of 1876-78, when millions died around the world because of intense droughts and famines, including in India.
In fact, monsoon regions in Asia witnessed their worst drought in 800 years during that period, according to a research paper published in the Journal of Climate in December 2018. According to the latest predictions by NOAA, there is an 82 per cent chance of El Niño developing during May-July 2026. There is also a 96 per cent chance that it could continue until the Northern Hemisphere winter season between December 2026 and February 2027.
IMD revises monsoon forecast to 90% of LPA, 60% chance of deficient rainfall
No IOD relief
A positive Indian Ocean Dipole (IOD), event could have counteracted some of the possible rainfall-suppressing impacts of El Niño. During a positive IOD, the western Indian Ocean becomes warmer than the eastern part, which can sometimes support rainfall over India.
But in its latest forecast, the IMD has predicted neutral IOD conditions in the Indian Ocean during the monsoon season.
Other unlikely weather events that could influence rainfall in the coming months are western disturbances, though their impact would be restricted to northwest India and some parts of central and northeastern India.
Western disturbances are extra-tropical storms in the upper layers of the atmosphere that travel from the Mediterranean, Caspian Sea and Black Sea regions to northwest India, bringing winter and spring precipitation.
In the past few years, because of a delayed retreat of the subtropical westerly jet stream, which carries western disturbances, and the presence of other forms of western disturbances not dependent on the jet stream, they have remained active over India even during summer and the monsoon season.
This unseasonal western disturbance activity can trigger extreme weather events such as incessant rainfall, flash floods, landslides and glacial lake outburst floods, mainly in the Himalayan regions, but sometimes also in adjoining plains.
Why is May cool? Varied weather systems have been active over India or the surrounding seas this month
Western disturbance threat
In the monsoon season of 2025, 17 western disturbances affected northwest India between June 1 and September 2, according to IMD data analysed by Down To Earth. In rare instances, there are around four western disturbances through the monsoon season, compared with the 17 recorded in 2025.
Western disturbances during the southwest monsoon season have led to catastrophic rainfall events in the past, such as the Uttarakhand cloudburst and flash floods of 2013, which killed more than 5,000 people.
The devastating floods in Punjab in August and September 2025, along with flash floods in Himachal Pradesh and other western Himalayan states, were also caused by active western disturbances interacting with several weather systems, including the monsoon low-pressure trough.
On June 3, with monsoon winds only a day away from onset, two western disturbances were active over northwest India, according to IMD data. Whether these weather systems remain active during the 2026 monsoon season and influence rainfall or trigger extreme weather events in northwest India, as they did last year, remains to be seen.