MUMBAI, May 26: The southwest monsoon has set in over Mumbai 16 days before the usual date, making it the earliest since 1950, the India Meteorological Department (IMD) said on Monday.
The primary rain-bearing system reached Kerala on Saturday, marking its earliest arrival over the Indian mainland since 2009, when it reached the southern state on May 23.
The southwest monsoon usually makes its onset over Kerala by June 1, reaches Mumbai by June 11 and covers the entire country by July 8. It starts retreating from northwest India around September 17 and withdraws completely by October 15.
According to the IMD’s Mumbai office, the data available since 1950 shows that this is the earliest arrival of the monsoon in the city.
Last year, the monsoon reached Mumbai on June 25. In preceding years, it arrived on June 11 in 2022, June 9 in 2021, June 14 in 2020, and June 25 in 2019. In 2020, the onset occurred on June 14, while in 2021 it was June 9.
Meteorologists emphasise that the date of monsoon onset has no direct correlation with the total seasonal rainfall..
The monsoon arriving early or late in Kerala or Mumbai does not mean it will cover other parts of the country. It is characterised by large-scale variabilities and global, regional and local features.
The IMD in April had made a forecast of an above-normal cumulative rainfall in the 2025 monsoon season, ruling out the possibility of El Nino conditions which are associated with below-normal rainfall in the Indian subcontinent.
Rainfall between 96 per cent and 104 per cent of the 50-year average of 87 cm is considered ‘normal’, the IMD states.
Rainfall less than 90 per cent of the long-period average is considered ‘deficient’; between 90 per cent and 95 per cent is ‘below normal’; between 105 per cent and 110 per cent is ‘above normal’; and more than 110 per cent is considered ‘excess’ precipitation.
India saw 934.8 mm of rainfall in 2024, 108 per cent of the average. (PTI)
