Monsoon Keeps India Waiting: Why the Official Onset Over Kerala Has Been Delayed

The southwest monsoon, which was expected to arrive early this year, has missed its first forecast date and is now likely to reach Kerala around June 4, according to the India Meteorological Department (IMD). While rain has already been reported in parts of the state, weather officials say the conditions required for an official declaration are still falling into place.

From May 26 Forecast to Another Delay

The monsoon season began attracting attention in May when the IMD predicted that it would reach Kerala by May 26, nearly a week ahead of its normal onset date of June 1. However, the expected advance slowed as atmospheric conditions weakened, forcing forecasters to revise the timeline.

The latest projections suggest the monsoon could make its official entry around June 4, though meteorologists continue to monitor conditions closely.

Why Rain Alone Doesn’t Mean Monsoon Has Arrived

Many parts of Kerala have already received showers, but rainfall by itself is not enough for the IMD to declare the onset of the southwest monsoon.

The weather department follows a scientific framework that requires three key conditions to be met together. These include widespread rainfall across designated weather stations, strong moisture-laden westerly winds over the Arabian Sea, and organised cloud systems indicating a sustained monsoon circulation.

If any of these elements are missing, the onset declaration is put on hold.

Winds Are Emerging as the Biggest Challenge

According to meteorologists, the main reason behind the delay is the absence of sufficiently strong and deep westerly winds.

These winds act as the monsoon’s transport system, carrying moisture from the Arabian Sea towards the Indian mainland. While rain-bearing clouds have developed over Kerala, the supporting wind patterns have not strengthened enough to indicate a fully established monsoon.

Recent model assessments suggest the required upper-level wind structure may become favourable only after June 5 or 6.

Cloud Activity Yet to Fully Organise

Another important factor is the development of deep convective clouds, a hallmark of an active monsoon system.

Weather scientists use satellite observations and a parameter known as Outgoing Longwave Radiation (OLR) to assess cloud intensity and organisation. Lower OLR values generally indicate thicker cloud cover and stronger atmospheric convection.

Officials say cloud activity has improved but has not remained organised enough for a formal onset declaration.

Why the Kerala Onset Matters to India

The arrival of the monsoon over Kerala marks the beginning of its annual journey across the country. Over the following weeks, the rain-bearing system advances northward, bringing much-needed rainfall to agricultural regions and replenishing reservoirs.

The southwest monsoon contributes more than 70 per cent of India’s annual rainfall and remains crucial for farming, drinking water supplies, hydropower generation and the broader economy.

What Happens Next?

With rainfall already present and atmospheric conditions gradually improving, meteorologists believe the official onset is not far away. The focus is now on whether the remaining wind and cloud benchmarks align over the next few days.

Until then, India continues to wait for the formal start of its most important weather season.

Read More: Agriculture Outlook For FY27 Hinges On Monsoon Progress, Distribution & El Nino Risk: RBI