Southwest Monsoon Arrives Over Kerala After Delay as IMD Confirms Full Onset Amid Expanding Rainfall System

The monsoon typically reaches Kerala around June 1. On May 15, the IMD had forecast its onset over the state around May 26, with a model uncertainty margin of plus or minus four days. The actual arrival on June 4, 2026, followed sustained atmospheric developments and widespread rainfall activity over Kerala.

In its statement, the IMD said the southwest monsoon has further advanced into the remaining parts of the southwest and southeast Arabian Sea, parts of the west-central and east-central Arabian Sea, the entire Lakshadweep Islands, Kerala and Mahe, parts of Karnataka and Tamil Nadu, the remaining Comorin region, and sections of the southeast Bay of Bengal, along with additional areas of the southwest, west-central, east-central, and northeast Bay of Bengal.

The northern limit of the monsoon currently passes through Mangalore, Uthagamandalam, Kodaikanal, and Thoothukudi. The IMD stated that conditions remain favourable for further advancement of the monsoon into additional regions over the next two to three days, including parts of the central Arabian Sea, Goa, Maharashtra, Andhra Pradesh, Karnataka, Tamil Nadu, the southwest Bay of Bengal, and parts of the northeastern states.

The weather agency noted an increase in convective cloud formation over the southeast Arabian Sea over the past two days. It further reported that the depth of westerly winds over the southeast Arabian Sea extends up to 4.5 kilometres above mean sea level, while lower-level westerly wind strength has been recorded at 20 to 25 knots.

The IMD also confirmed widespread rainfall, including isolated heavy showers over Kerala during the past two days. Based on these combined meteorological conditions, it declared the official onset of the southwest monsoon over Kerala on June 4, 2026.

Meanwhile, developments in global climate patterns are being closely monitored. Reports indicate that El Niño conditions are emerging, with potential implications for global temperature and rainfall distribution. According to the World Meteorological Organization, there is an 80 percent probability of an El Niño event between June and August 2026.

The probability of El Niño conditions persisting until at least November is estimated to be near or above 90 percent, with several forecast models suggesting the event could range from moderate to strong intensity.

A seasonal outlook issued on April 30 by the World Meteorological Organization indicated that rainfall during the June to September 2026 southwest monsoon season is likely to remain below normal across much of South Asia, with the most pronounced impact expected over central regions.

The arrival of the monsoon in Kerala under these evolving atmospheric conditions underscores a critical phase in the seasonal climate cycle, with implications for rainfall distribution across the Indian subcontinent in the coming months.