Kerala Monsoon Arrival Delayed, IMD Now Expects Onset by June 3
IMD Delays Kerala Monsoon Onset, Arrival Now Expected by June 3
May 28: The India Meteorological Department (IMD) has revised its forecast for the onset of the southwest monsoon over Kerala, pushing the expected arrival window from the earlier prediction of May 26 to between May 28 and June 3.
The update comes as several key meteorological conditions required for the official declaration of monsoon onset are yet to be fully met. Although weather activity has intensified across parts of the southern Arabian Sea and Kerala coast, the IMD said the atmosphere is still under observation before a formal announcement is made.
According to the IMD’s latest monsoon progress outlook, the southwest monsoon is expected to reach Mumbai between June 5 and June 10, while its arrival over Delhi is likely around June 27, following its gradual advance across the country.
The onset of the monsoon over Kerala is considered a significant indicator for India’s annual rainy season, which plays a crucial role in agriculture, water supply, power generation, and the overall economy. A timely monsoon is particularly important for farmers preparing for the kharif sowing season.
The IMD follows a strict scientific process before officially declaring the onset of the monsoon over Kerala. One of the key criteria is that at least 60 percent of the 14 designated weather stations across Kerala and Lakshadweep must record rainfall of 2.5 mm or more for two consecutive days.
In addition to rainfall, atmospheric conditions are also monitored closely. Strong westerly winds at around 4.5 km altitude are expected to reach speeds between 28 and 37 kmph. Meteorologists also examine Outgoing Longwave Radiation (OLR) levels, which help determine cloud density and convective activity over the region. Lower OLR values generally indicate widespread cloud formation and active monsoon conditions.
Only after all these parameters are satisfied does the IMD officially announce the onset of the southwest monsoon over Kerala.
A comparison of monsoon onset dates over the last few years shows noticeable variation. The monsoon arrived on June 1 in 2020, June 3 in 2021, May 29 in 2022, June 8 in 2023, and May 30 in 2024. In 2025, the monsoon arrived unusually early on May 24.
Weather experts say slight changes in onset dates are common and do not necessarily indicate the overall performance of the monsoon season. However, the progress of the monsoon is being closely watched amid rising temperatures and increasing concerns over heatwave conditions across several parts of India.
