The southwest monsoon is expected to reach Kerala on May 26, nearly six days ahead of its normal onset date of June 1, according to the India Meteorological Department (IMD).
While the early arrival has raised hopes for relief from intense summer heat, weather experts have cautioned that a possible El Niño event later this year could weaken rainfall during the core monsoon season.
The IMD said weather conditions are becoming favourable for the monsoon to advance over parts of the south Bay of Bengal, the Andaman Sea and the Andaman and Nicobar Islands. Heavy rainfall activity is also expected along the southern west coast until May 28.
Early Monsoon Arrival Brings Hope Amid Heatwave
India has been witnessing severe heatwave conditions across several northern and central states. The early arrival of the monsoon is likely to bring cooler temperatures and rainfall to southern regions, especially Kerala, Karnataka and Tamil Nadu.
According to IMD officials, the forecast carries an error margin of four days. In 2025, the monsoon reached Kerala on May 24, making this year’s projected arrival relatively close to last year’s timeline.
However, meteorologists clarified that an early onset does not guarantee above-normal rainfall across the season.
Experts Warn Early Onset Does Not Mean Strong Monsoon
Weather experts said the strength and distribution of monsoon rainfall depend on several atmospheric factors, including the formation of low-pressure systems and moisture surges.
Mahesh Palawat, Vice President of Climate and Meteorology at Skymet Weather, explained that there is no direct connection between early monsoon arrival and the total seasonal rainfall.
“In some years, the monsoon arrives early but overall rainfall remains below normal. The movement and intensity of rain-bearing systems determine the final outcome,” he said.
El Niño Threat Could Impact India’s Rainfall
Global climate agencies are closely monitoring the possible development of El Niño conditions in the Pacific Ocean. Scientists from the US National Oceanic and Atmospheric Administration (NOAA) have warned that El Niño is likely to emerge soon and may strengthen significantly between September and November.
An El Niño event is generally linked to weaker monsoon rainfall, rising temperatures and drier conditions across India. The IMD has already projected below-normal rainfall for the June-to-September monsoon season at 92% of the Long Period Average (LPA).
Large parts of the country are expected to receive below-normal rainfall, while some areas in northeast India, northwest India and southern peninsular regions may receive normal or above-normal showers.
IMD Explains How Monsoon Onset Is Forecast
The IMD uses an indigenous statistical model developed in 2005 to forecast the onset date over Kerala. The model analyses six key weather indicators, including:
- Minimum temperatures over northwest India
- Pre-monsoon rainfall activity over south India
- Outgoing Longwave Radiation (OLR) patterns
- Wind patterns over the Indian Ocean region
These indicators help scientists estimate the timing and movement of the monsoon system.
Heavy Rainfall And Heatwave Alerts Continue
Along with monsoon developments, the IMD also reported a well-marked low-pressure area over the Bay of Bengal. The system is likely to trigger heavy to very heavy rainfall in parts of northeast India, Kerala, Tamil Nadu, Puducherry, Karaikal and south interior Karnataka over the next few days.
At the same time, heatwave to severe heatwave conditions are expected to continue over northwest and central India through the week.
