India's southwest monsoon ends with 12.6% rainfall deficit, fourth-lowest since 2001

India's southwest monsoon ended on Wednesday with rainfall 12.6% below normal, making the 2026 season the fourth-driest monsoon since 2001, according to the India Meteorological Department (IMD).

The country received 759.4 mm of rainfall between June and September, against the long-period average of 868.6 mm. The season was also the driest in more than a decade, with rainfall at about 87% of the long-period average.

The deficit was particularly pronounced in eastern, northeastern and southern parts of the country. East and Northeast India recorded a 25% rainfall deficit, while South Peninsular India was 24% below normal. Northwest India recorded a 6% deficit, while central India was broadly near normal with a 2% shortfall.

Rainfall remained uneven through the season

The monsoon got off to a weak start, with the weekly rainfall deficit reaching 51.1% in the week ending July 15. Rainfall improved in late July and early August but turned deficient again from mid-August, with the weekly shortfall reaching 36.3% in the week ending September 9.

June recorded the sharpest monthly deficit at 35.4%, while August and September registered shortfalls of 16.3% and 7.6%, respectively. July was the only month to record above-normal rainfall, with a surplus of 1%.

Of the country's 36 meteorological subdivisions, 17 recorded deficient rainfall, covering about 42% of India's area, while 18 subdivisions covering around 53% of the area received normal rainfall.

El Niño weighs on monsoon performance

The below-normal rainfall came amid strengthening El Niño conditions in the tropical Pacific, which are generally associated with weaker monsoon rainfall over India.

IMD Director General Mrutyunjay Mohapatra said El Niño is expected to peak in November before gradually weakening, with the event likely to continue into early 2027. Despite the adverse conditions, the formation of low-pressure systems helped sustain rainfall over parts of central India. The IMD recorded 77 low-pressure-system days during the season, compared with a normal of 57 days.

The rainfall deficit was particularly severe in East and Northeast India, which recorded its lowest monsoon rainfall since 1901. South Peninsular India experienced its fourth-lowest monsoon rainfall on record.

October likely to remain drier

The IMD expects the rainfall deficit to persist into October, forecasting rainfall below 85% of the long-period average across India as a whole.

Most parts of the country are likely to receive below-normal rainfall during October, although some areas of northwest India, southern Peninsular India and isolated parts of eastern India could receive normal to above-normal rainfall. The October-December period is also expected to bring below-normal rainfall to most parts of the country.

The IMD has also forecast above-normal maximum temperatures across most of India during October, along with above-normal minimum temperatures in large parts of the country.

The weaker monsoon could have implications for soil moisture, reservoir storage and agriculture ahead of the rabi sowing season, particularly in regions that experienced prolonged rainfall deficits.