Mumbai has witnessed the earliest onset of the southwest monsoon since 1950, arriving 16 days ahead of the usual June 11 date, according to the India Meteorological Department (IMD). The rain-bearing system first reached Kerala on Saturday, marking its earliest landfall over the Indian mainland since 2009, when it arrived on May 23.
Historically, the southwest monsoon makes its way to Kerala by June 1, progresses to Mumbai by mid-June, and covers the entire country by July 8. It typically begins withdrawing from northwest India around September 17 and completes its retreat by October 15.
IMD’s Mumbai office confirmed that data since 1950 reflects this year’s arrival as the city’s earliest on record. Last year, Mumbai saw the monsoon on June 25. In recent years, it arrived on June 11 in 2022, June 9 in 2021, June 14 in 2020, and again June 25 in 2019.
Meteorologists clarify that the timing of monsoon onset doesn’t directly correlate with the total seasonal rainfall. The monsoon’s spread across India is influenced by a complex mix of global, regional, and local climatic factors, making early or late arrival an unreliable predictor of overall intensity.
In April, the IMD forecast above-normal cumulative rainfall for the 2025 monsoon season, dismissing the likelihood of El Niño conditions, which are typically linked with drought-like scenarios in India.
As per IMD standards, seasonal rainfall between 96 per cent and 104 per cent of the 50-year average of 87 cm is considered normal. Less than 90 per cent is termed deficient, 90–95 per cent is below normal, 105–110 per cent is above normal, and anything beyond 110 per cent is categorized as excess.
India recorded 934.8 mm of rainfall in 2024, or 108 per cent of the long-period average. By comparison, the country received 820 mm in 2023 (94.4 per cent), 925 mm in 2022, 870 mm in 2021, and 958 mm in 2020.
The monsoon remains critical for India’s economy, particularly its agricultural sector, which supports about 42 per cent of the population and contributes 18.2 per cent to the nation’s GDP. It provides essential water for crops, drinking water supply, hydropower generation, and reservoir replenishment.
