Rain clouds gather over Kochi city on May 15, 2024.

Rain clouds gather over Kochi city on May 15, 2024.
| Photo Credit: H. Vibhu

The southwest monsoon is likely to arrive over Kerala around May 31, setting the stage for the four-month rainfall season crucial for India’s farm-based economy.

“This year, the southwest monsoon is likely to set in over Kerala on May 31 with a model error of four days,” the India Meteorological Department said on Wednesday.

“This is not early. It’s close to the normal date,” IMD Director General Mrutyunjay Mohapatra said.

The date of monsoon onset over Kerala has varied widely over the last 150 years, the earliest being May 11 in 1918, and the most delayed being June 18 in 1972, according to IMD data.

The rain-bearing system arrived in the southern State on June 8 in 2023, May 29 in 2022, June 3 in 2021 and June 1 in 2020.

In April, the IMD had forecast above-normal rain in the monsoon season in India with favourable La Nina conditions expected to set in by August-September.

Parts of the country battled brutal heat in April, with maximum temperatures shattering records in several states and severely impacting health and livelihoods.

The crippling heat is straining power grids and drying up water bodies triggering drought-like conditions in parts of the country. A prediction of above-normal monsoonal rainfall, therefore, comes as a huge relief.

The monsoon is critical for India’s agricultural landscape, with 52 per cent of the net cultivated area relying on it. It is also crucial for replenishing reservoirs critical for drinking water, apart from power generation across the country.

June and July are considered the most important monsoon months for agriculture because most of the sowing for the Kharif crop takes place during this period.

El Nino conditions are prevailing at present, and La Nina may set in by August-September, scientists say.

El Nino — the periodic warming of surface waters in the central Pacific Ocean — is associated with weaker monsoon winds and drier conditions in India. La Nina — the antithesis of El Nino — leads to plentiful rainfall during the monsoon season.

The IMD is also anticipating the development of a positive Indian Ocean Dipole (IOD) or cooler-than-normal Indian Ocean in the east compared to the west, which helps bring rain to several states in southern India. The IOD is currently ‘neutral’ and is expected to turn positive by August.

Another factor is below-normal snow cover in the northern hemisphere and Eurasia. Historically, there has been an “inverse relationship” between the levels of snow here and the monsoon.

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