India’s southwest monsoon has swung between dry spells and extreme rainfall, leaving the country 16% rain-deficient as of July 27.
More than half of India’s districts have received deficient or large deficient rainfall, even as floods, flash floods and landslides have hit several states.
Assam is facing floods despite a 30% rainfall deficit, underlining how short, intense rain spells can cause disasters during a weak monsoon.
Scientists say the uneven season is being shaped by natural monsoon variability, strengthening El Niño, western disturbances and global warming.
India’s Southwest Monsoon 2026 has swung between dry spells and intense rainfall since it began on June 4, 2026, bringing floods, flash floods and landslides to parts of the west, northwest and northeast even as several states continue to report rainfall deficits.
Active and break phases are a normal feature of the monsoon. But scientists say the intensity of the dry spells, and the extreme rainfall during active periods, is a growing concern.
This year’s erratic monsoon pattern may be influenced by a strengthening El Niño phenomenon in the equatorial Pacific Ocean, as well as warming driven by greenhouse gas emissions. The world has already warmed by about 1.4 degrees Celsius above pre-industrial levels.
There is an 81 per cent chance of a very strong, or “super”, El Niño between October and December, according to the latest update from the United States’ National Oceanic and Atmospheric Administration. El Niño is the warmer-than-normal phase of the El Niño Southern Oscillation in the equatorial Pacific Ocean, which generally suppresses monsoon rainfall over India.
Daily rainfall data from the India Meteorological Department (IMD) shows that the monsoon was in an active phase, with normal to above-normal rainfall over the country, between June 29 and July 9, and again from July 19 to 24. Another active spell could begin from July 28, as a deep depression over the eastern coast starts moving inland.
But active monsoon phases do not produce rainfall evenly across the country. Within the same spell, some regions may receive exceptionally heavy rainfall while others receive little rain. Despite two active phases over several regions, India’s nationwide rainfall deficit stood at 16 per cent on July 27.
East and northeast India recorded the highest deficit, at 30 per cent, followed by the southern peninsula at 29 per cent. Central India received 4 per cent less rain than normal, while northwest India had a deficit of 10 per cent.
State and district-level data show how uneven the season has been. Nineteen states and union territories recorded deficient rainfall between June 1 and July 27, according to IMD data.
Meghalaya, often called the “abode of clouds”, recorded the highest deficit, at 56 per cent. Ladakh, a cold desert, recorded the largest excess, at 196 per cent.
The district-level picture is also uneven. About 53 per cent of districts recorded deficient rainfall, meaning 20 per cent to 59 per cent below normal, or large deficient rainfall, meaning 60 per cent to 99 per cent below normal.
Only 12 per cent of districts received excess rainfall, meaning 20 per cent to 59 per cent above normal, or large excess rainfall, more than 60 per cent above normal. Another 34 per cent of districts recorded normal rainfall.
Even as many regions remain rain-deficient, several states have seen extreme rainfall over short periods, leading to riverine floods, flash floods and landslides. Assam, despite a 30 per cent rainfall deficit, is facing floods in 12 districts at present. More than 700,000 people across 856 villages were affected as of July 25, according to data from Sphere India.
Much of the flooding has been linked to rivers flowing into Assam from Nagaland, which has also experienced extreme rainfall, flash floods and landslides.
Other states and union territories affected by extreme rainfall, floods, flash floods or landslides include Mizoram, Jammu and Kashmir, Himachal Pradesh, Gujarat and Maharashtra.
“Monsoon has active and break periods and El Niño tends to increase breaks in number and duration,” Raghu Murtugudde, emeritus professor at the University of Maryland and visiting professor at the Indian Institute of Technology Kanpur, told Down To Earth. “July and August are peak monsoon months, so active spells are expected. Global warming tends to produce extreme spells in both active and break periods.”
Another factor adding to the complexity of this year’s monsoon is the continued activity of western disturbances through June and July. Western disturbances are extra-tropical weather systems in the upper atmosphere that move eastwards from the Mediterranean region and bring winter precipitation to northwest India.
They are usually less active during the monsoon season. But in 2025 and 2026, they have remained active during the monsoon as well.
This year, some of the extreme rainfall and landslides in the Himalayan region have occurred when western disturbances interacted with the monsoon. This has been particularly visible in Jammu and Kashmir, where both systems have been active.
“Northwest India is getting heavier spells, as expected from the northward shift of southwesterly winds caused by west Asian warming,” Murtugudde said. “So all these factors are playing together to produce the ups and downs: natural variability of the monsoon itself, El Niño adding to it, and all of it being modulated by global warming.”