El Nino Forecast 2026: Southwest Monsoon Arrives in Andaman & Nicobar; Expected to Hit Kerala Within 10 Days

The southwest monsoon has officially entered the Andaman and Nicobar Islands, marking the beginning of India's most closely watched weather season. The India Meteorological Department (IMD) said the monsoon advanced over large parts of the south Bay of Bengal, the Andaman Sea and the entire Nicobar Islands on May 16, and is now expected to reach Kerala around May 26 - nearly a week ahead of its normal onset date of June 1.

Monsoon Arrives in India's Andaman and Nicobar Islands; Expected to Hit Kerala Within 10 Days

If the monsoon reaches Kerala on the projected date, it would be one of the earliest arrivals in recent years and could provide an encouraging start to the 2026 rainy season. The monsoon is crucial for India's agriculture, water reservoirs, hydroelectric generation and inflation outlook, as nearly half of the country's farmland still depends on rainfall rather than irrigation.

IMD Weather Alert: Southwest Monsoon Advances Across Bay of Bengal

In its latest bulletin, the IMD said the monsoon has advanced into parts of the southeast Arabian Sea, southwest and southeast Bay of Bengal, much of the Andaman Sea, and the entire Nicobar Islands, including Sri Vijaya Puram. This early progress indicates that atmospheric and oceanic conditions are currently favourable for further advancement toward the Indian mainland.

El Nino Forecast: Stronger El Nino in Late 2026 May Trigger Drought in Some Areas and Floods in Others

While the early onset has generated optimism, meteorologists caution that the broader monsoon season may still face significant challenges. A developing El Niño event in the Pacific Ocean is expected to strengthen later in the year and could disrupt rainfall patterns across India, particularly during August and September.

El Nino is a climate phenomenon caused by abnormal warming of sea surface temperatures in the central and eastern Pacific Ocean. This warming alters global wind circulation and often weakens the moisture-laden monsoon winds that bring rainfall to the Indian subcontinent.

According to current observations, Pacific Ocean temperatures in key monitoring zones are already about 0.5 degrees Celsius above normal, signalling the early stages of El Nino development. Several global climate models suggest the event may intensify significantly during the second half of 2026.

IMD Forecasts Below-Normal Rainfall for 2026 Monsoon Season

In its first long-range forecast issued in April, the IMD projected that India is likely to receive around 92% of the long-period average rainfall during the June-to-September southwest monsoon season. This places the 2026 season in the "below normal" category.

The long-period average rainfall for the country, based on data from 1971 to 2020, is approximately 870 millimetres. The IMD has estimated a 35% probability that rainfall could fall into the "deficient" category, defined as less than 90% of the long-period average. Historically, the probability of such a deficient monsoon has been around 16%, highlighting elevated weather risks this year.

Meteorologists believe states such as Punjab, Haryana, Rajasthan and large parts of Madhya Pradesh may experience prolonged dry spells during the latter half of the monsoon, increasing the risk of drought and crop damage.

Major urban centres, including Delhi and the National Capital Region, may also receive below-normal rainfall, offering limited relief from heatwaves and potentially worsening water shortages.

In contrast, Chennai and coastal Tamil Nadu may face periods of intense rainfall and local flooding, a pattern that has emerged during several previous El Nino years.

2015 Drought and Chennai Floods to 2023 Rainfall Shock: How El Nino Impact India in Past

Historical data illustrate the risks associated with strong El Nino events. During the 2015-16 super El Nino, India received only 86% of average monsoon rainfall, leading to severe drought in several regions. At the same time, Chennai experienced catastrophic flooding caused by concentrated bursts of extreme rainfall.

In 2023, another El Nino year, India recorded a 36% rainfall deficit in August, causing significant stress in parts of Maharashtra, Madhya Pradesh, Odisha and Chhattisgarh.

If El Nino intensifies as projected, India could experience a highly uneven monsoon season, with some regions battling drought while others face damaging floods.

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