MUMBAI: Mumbai experienced its heaviest May rainfall in more than a century as the southwest monsoon arrived 16 days ahead of schedule, shattering weather records and prompting red alerts across coastal Maharashtra. The heaviest Mumbai rainfall 100 years was recorded on 26 May 2025, with 295 mm falling at Colaba observatory—surpassing a record set in 1918.

The India Meteorological Department (IMD) confirmed that this is the earliest onset of monsoon in Mumbai in the last 75 years. Typically expected by 11 June, the monsoon’s arrival on 26 May marks a rare shift, significantly altering weather patterns across the state. The IMD officially upgraded Mumbai and neighbouring districts like Thane, Raigad, and Ratnagiri from orange to red alert as rains continue to batter the region.

South Mumbai bore the brunt of the rainfall, with several areas inundated and registering over 200 mm of rain within just 11 hours. The heaviest Mumbai rainfall 100 years has intensified concerns about the city’s preparedness for future climate extremes.

IMD scientist Sushma Nair described the event as “a significant climatic occurrence,” noting that the current rainfall levels far exceed seasonal norms. The city is experiencing temperatures between 23°C and 32°C, with overcast conditions and heavy showers forecast to continue through Tuesday.

Beyond Mumbai, the monsoon has also advanced across parts of Karnataka, Kerala, Tamil Nadu, Telangana, and the northeast. However, the focus remains on Mumbai, where the heaviest Mumbai rainfall 100 years has disrupted transport, led to power outages in some areas, and tested municipal infrastructure.

This record-breaking event highlights the urgent need for sustainable urban planning and robust disaster response systems as climate variability becomes increasingly unpredictable in South Asia’s major cities.

-Agencies