The India Meteorological Department (IMD) has revised the anticipated arrival date of the southwest monsoon over Kerala to June 4, 2026, a delay from the earlier predicted date of May 26 and the normal onset date of June 1. This adjustment was announced on June 2, 2026, following an earlier acknowledgment on May 29 that the monsoon was unlikely to reach Kerala within the four-day forecast window. The IMD’s operational forecasts of monsoon onset over Kerala have been accurate in 20 out of the last 21 years (2005–2025), with only 2015 being an exception where the arrival fell outside the forecasted four-day window.
While the timing of the monsoon’s arrival does not directly influence the total rainfall quantum, this year’s delayed onset has raised concerns about the overall rainfall distribution. The IMD and other global weather agencies have warned of below-normal rainfall during the monsoon season. The agency stated in its daily bulletin on June 1, 2026, that favorable conditions are developing for the further advance of the southwest monsoon into parts of the southwest and southeast Arabian Sea, Lakshadweep Islands, Kerala, Tamil Nadu, and multiple regions of the Bay of Bengal over the next 2–3 days.
In addition to the delayed onset, the IMD has reduced its seasonal rainfall forecast to 90% of the Long Period Average (LPA), down from the 92% projection issued in April. Under IMD’s classification, any monsoon season receiving less than 90% of the LPA is categorized as “deficient.” This marks a downward revision from earlier expectations and signals potential water stress and agricultural challenges across the country.
One of the primary factors contributing to the below-normal rainfall forecast is the emergence of El Nino conditions in the equatorial Pacific region. The IMD noted that neutral El Nino-Southern Oscillation (ENSO) conditions are currently transitioning toward El Nino. While El Nino conditions are expected to remain weak in June, they are likely to strengthen to moderate to strong levels by September, which typically suppresses monsoon rainfall in India.
Last year, the southwest monsoon arrived over Kerala on May 24, 2025 — its earliest onset since 2009 — demonstrating the variability that can occur in monsoon timing despite broader climatic trends. The IMD highlighted that while the onset date is closely monitored, it is not a reliable indicator of the total rainfall the country will receive during the season.
The southwest monsoon is critical for India’s agricultural sector, which relies heavily on timely and adequate rainfall for kharif crop cultivation. A deficient monsoon can lead to reduced reservoir levels, lower groundwater recharge, and adverse impacts on rural incomes and food production. With El Nino conditions developing, farmers and policymakers are likely to increase preparedness for potential water shortages and drought-like conditions in several regions.
The IMD continues to monitor weather patterns and will provide updated forecasts as the monsoon progresses across the subcontinent.
