As large parts of India continue to reel under intense summer heat, attention is now shifting to the arrival of the southwest monsoon — the weather system that delivers nearly 70% of the country’s annual rainfall and plays a crucial role in agriculture, water supply and power demand. 

According to the India Meteorological Department (IMD), the southwest monsoon is expected to reach the Kerala coast around its normal onset date in early June, even as some global weather models hint at a slightly early arrival this year. 

IMD Director General Mrutyunjay Mohapatra said monsoon rains are likely to begin over the Andaman and Nicobar Islands between May 14 and May 20 — an important early milestone in the monsoon’s journey toward mainland India. 

What is the usual monsoon timeline? 

Under normal conditions, the southwest monsoon follows a fairly predictable progression across the country: 

• Kerala: Around June 1 
• Mumbai: Around June 10 
• Central India: Mid-June 
• Delhi-NCR: Around June 27 to June 30 
• Entire country covered: By around July 15 

The IMD notes that the monsoon typically advances northward in phases or “surges”, influenced by sea surface temperatures, wind patterns and low-pressure systems over the Bay of Bengal and Arabian Sea. 

Is monsoon arriving early this year? 

While the IMD has not yet officially declared an early onset, several international weather models, including the European Centre for Medium-Range Weather Forecasts (ECMWF), suggest the monsoon may reach Kerala by the last week of May. 

Some forecasts indicate that monsoon currents could reach the Andaman region as early as May 18 and advance rapidly toward southern India if atmospheric conditions remain favourable. 

However, weather experts caution that an early onset over Kerala does not always mean the monsoon will advance quickly across the entire country. In some years, progress slows after the initial onset phase due to changing wind conditions and rainfall patterns. 

IMD predicts below-normal seasonal rainfall 

In its first long-range forecast issued in April, the IMD predicted that India is likely to receive below-normal monsoon rainfall during the June-September season. Rainfall is estimated at 92% of the Long Period Average (LPA), with the possibility of El Niño conditions developing later in the monsoon season. 

The weather agency said neutral conditions currently prevail in the Pacific Ocean, but climate models indicate El Niño could emerge by July, potentially affecting rainfall distribution across India. 

At the same time, the IMD expects pre-monsoon rainfall activity in May to remain normal to above normal across many regions, offering some relief from ongoing heatwave conditions. 

The southwest monsoon is critical for India’s economy, especially the farm sector. A large part of India’s kharif crop cultivation depends on timely and well-distributed rainfall. Reservoir levels, hydropower generation and rural consumption are also closely linked to monsoon performance.

Published on: May 2, 2026 1:54 PM IST