India's crucial southwest monsoon is set to arrive in Kerala today, June 4, according to the India Meteorological Department (IMD). This arrival marks a delay from its original forecast of May 26 and a subsequent revised projection for June 1, initiating the country's vital four-month rainy season.
Delayed Start to Monsoon Season
The IMD had initially predicted the monsoon's onset over Kerala on May 26. After this date passed without its arrival, the department revised its outlook on May 29, suggesting the onset would occur in the first week of June. The traditional start date for the monsoon in Kerala is typically around June 1, signaling the commencement of India's primary rainfall period from June to September.
Below-Normal Rainfall Projected
Adding a layer of concern, the IMD has also revised its overall forecast for the 2026 monsoon season, projecting below-normal rainfall across the country. India is expected to receive approximately 90 percent of the Long Period Average (LPA) this year. The LPA, defined as the average rainfall over a specific region during a period of 30 to 50 years, stands at 87 cm for seasonal rainfall across India based on 1971-2020 data. Rainfall below 90 percent of the LPA is classified as "deficient" by the IMD.
El Niño Conditions a Key Factor
A significant reason cited for the anticipated below-normal rainfall is the potential development of El Niño conditions. These climatic patterns are generally linked to weaker monsoon rainfall across India. Currently, neutral El Niño-Southern Oscillation conditions are transitioning towards El Niño over the equatorial Pacific region. The IMD indicates that while El Niño conditions are likely to remain weak through June, they are expected to strengthen to moderate or strong levels by September.
Beyond Kerala, conditions are also favorable for the further advance of the southwest monsoon into additional parts of the southwest and southeast Arabian Sea, Lakshadweep Islands, and some areas of Tamil Nadu around the same time. The monsoon is also expected to progress into more parts of the southwest, west-central, east-central, and northeast Bay of Bengal, as well as the remaining parts of the southeast Bay of Bengal.