Mumbai Witnesses Record-Breaking Rainfall
Although the southwest monsoon arrived late in Mumbai this year, it unleashed exceptionally heavy rainfall over the past week, breaking several long-standing records. Between late June and July 8, the city recorded its highest rainfall for this period since 2000. By July 6, Mumbai had already received nearly 1,240 mm of rain, causing severe flooding across the metropolitan region.
At the Colaba Observatory, 791 mm of rainfall was recorded between July 1 and July 7—almost equal to the area’s average rainfall for the entire month of July. Meanwhile, the Santacruz Observatory received 879 mm during the first week of July, close to its monthly average of 919.9 mm. On July 5 alone, Colaba recorded over 225 mm of rainfall, while Santacruz registered 268 mm within 24 hours, making it the second-highest one-day July rainfall there in the past 15 years.
Why Did Heavy Rainfall Occur During an El Niño Year?
According to scientists from the India Meteorological Department (IMD), several climate factors combined to produce this extreme weather despite El Niño, which typically suppresses monsoon rainfall.
A key reason was the record-high sea surface temperatures in the Arabian Sea. Warmer waters increased evaporation, supplying enormous amounts of moisture to the atmosphere. At the same time, low-pressure systems from the Bay of Bengal tracked westward across central India instead of moving northwest, allowing moisture from both the Arabian Sea and Bay of Bengal to converge over western India.
The Western Ghats further intensified rainfall by forcing moisture-laden winds to rise, leading to continuous cloud formation and intense downpours over Mumbai.
Climate Change Is Intensifying Extreme Rainfall
Experts say global warming is fundamentally altering monsoon behaviour. A warmer atmosphere can hold about 7% more moisture for every 1°C rise in temperature, resulting in shorter but much more intense rainfall events.
Former IMD Director General K.J. Ramesh and climate scientist Dr. Raghu Murtugudde emphasized that El Niño can no longer be studied in isolation. The interaction between El Niño and climate change is making rainfall increasingly erratic, with fewer rainy days but more frequent cloudbursts and urban flooding across India.