Monsoon expected early again, Kerala onset around May 26: IMD

Amid apprehensions of economic slowdown exacerbated by multiple factors such as crude oil price shock and currency depreciation triggered by the US-Iran conflict and disruptions in the Strait of Hormuz, there seems to be some positive news regarding the southwest monsoon—the most awaited weather phenomenon in the country every year. The monsoon, this year, is again expected to arrive early over Kerala with the India Meteorological Department (IMD) forecasting its onset around May 26, with a model error margin of ±4 days.

The monsoon, which typically strikes the southernmost tip of India around June 1, may mark its third consecutive early arrival if the forecast holds true. It reached Kerala on May 27 in 2025 and May 31 in 2024.

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According to the IMD, conditions are currently favourable for the advance of the southwest monsoon over parts of the south Bay of Bengal, the Andaman Sea, and the Andaman & Nicobar Islands within the next 24 hours. Usually, the monsoon first sets in over the South Andaman Sea around May 22 before progressing towards the Indian mainland.

While the early onset brings cautious optimism, weather forecasts for the rest of the country remain mixed. The IMD warned that severe heatwave conditions are likely to continue over northwest and central India during the ongoing week. Meanwhile, isolated heavy to very heavy rainfall is expected over the northeast this week, and over Tamil Nadu, Puducherry and Karaikal, Kerala and Mahe, and South Interior Karnataka over the next 3–4 days.

For India, the June–September seasonal rains are critical as they deliver over 70% of annual rainfall, shaping agriculture, water availability, reservoir levels, and overall economy of the country. This year, however, the IMD’s seasonal outlook is indicating below normal rains. The weather office has projected rainfall at about 92% of the Long Period Average (LPA), within a model error margin of ±5%. The LPA, based on data from 1971–2020, is 87 cm.

Meteorologists say that at present, weak La Niña–like conditions are transitioning to ENSO-neutral conditions over the equatorial Pacific. Atmospheric circulation features across the tropical Pacific remain consistent with weak La Niña–like conditions. The Monsoon Mission Climate Forecast System (MMCFS) suggests the development of El Niño conditions during the season.

A respite is the neutral Indian Ocean Dipole (IOD) conditions over the Indian Ocean. The latest climate model forecasts also indicate that positive IOD conditions are likely to develop towards the end of the season.

A positive IOD is generally good for the monsoon. It creates warmer sea surface temperatures in the western Indian Ocean, which increases moisture transport towards the subcontinent, often leading to above-normal rainfall and acting as a counter to dry El Niño conditions, according to analysts. Also, the Northern Hemisphere snow cover extent during the past three months (January to March 2026) was slightly below normal. Winter and spring snow cover over the Northern Hemisphere, as well as Eurasia, has a general inverse relationship with the subsequent seasonal rainfall over the country.