Southwest monsoon set to arrive in Kerala early; could be earliest onset since 2009

The IMD had earlier forecast the monsoon’s arrival in Kerala around May 27—well ahead of the usual onset date of June 1.

May match 2009 record

If the monsoon enters Kerala as expected, it would be the earliest onset since 2009, when the season began on May 23, according to IMD records.

On average, the southwest monsoon reaches Kerala by June 1 and sweeps across the entire country by July 8. It begins to withdraw from northwest India around September 17 and fully retreats by October 15.

Recent onset dates for the monsoon in Kerala include May 30 in 2024, June 8 in 2023, May 29 in 2022, June 3 in 2021, and June 1 in 2020. The last time it arrived this early was on May 23 in 2009, the earliest onset in recent years.

The last notably early onset was on May 23 in 2009.

The IMD defines a ‘normal’ monsoon as cumulative rainfall amounting to 96–104 per cent of the 50-year average of 87 cm.

Outlook positive as El Niño risk fades

In its April forecast, the IMD projected above-normal rainfall for the 2025 monsoon season and ruled out the emergence of El Niño conditions—often associated with deficient rainfall in India.

The absence of El Niño this year signals a favourable outlook for the monsoon, raising hopes for strong agricultural output and a boost in rural demand.