Mumbai has been lashed by heavy monsoon rains as the annual southwest monsoon arrived early in Maharashtra, marking the earliest onset in 35 years. The India Meteorological Department (IMD) has issued alerts, with some areas receiving record-breaking rainfall. The early arrival of the monsoon has disrupted daily life, causing traffic congestion, train delays, and waterlogging in several parts of the city.

The southwest monsoon's arrival in Maharashtra on May 25, 2025, was the earliest since 1990. The monsoon's arrival in Kerala on May 24, nearly a week ahead of the usual date of June 1, signaled the early shift in weather patterns. The IMD had earlier predicted above-normal rainfall for the 2025 season, dismissing concerns about El Nino.

Mumbai experienced thunderstorms, lightning, and gusty winds. Suburban rail services were affected, and traffic slowed down due to poor visibility. An 'orange' alert was initially issued for Mumbai, Raigad, Ratnagiri, Thane, Pune, and Kolhapur districts, but was upgraded to 'red', indicating the possibility of extremely heavy rainfall. The Navi Mumbai Municipal Corporation was put on high alert due to the continuous downpour.

Several parts of Mumbai, particularly in South Mumbai, received over 200 mm of rain. The coastal observatory in Colaba recorded 135 mm of rainfall. Between 9 and 10 am, Nariman Point registered 104mm of rainfall, among the highest hourly totals of the season. The heavy rainfall shattered a 107-year-old record for the month of May.

Waterlogging was reported in areas such as King Circle and Sion, disrupting traffic. Local train services on the Central Railway and Harbour Line faced delays due to waterlogged tracks. BEST bus routes were diverted due to road issues and water accumulation. A newly inaugurated Worli underground metro station was flooded, with passengers wading through water on the platforms.

The IMD has predicted that the monsoon will advance further into Mumbai, Bengaluru, and parts of Andhra Pradesh and Tamil Nadu over the next few days. While an early monsoon onset is generally welcomed, the heavy rainfall has raised concerns about potential damage to crops and infrastructure. Unseasonal rains have already damaged onion crops in Maharashtra.

Authorities have advised citizens to remain cautious, avoid non-essential travel through waterlogged areas, and stay updated with official advisories from the Brihanmumbai Municipal Corporation (BMC) and Mumbai Police. Water transport services between Mandva (Alibag) and Mumbai have been suspended due to the monsoon season. The State Disaster Management Control Room is coordinating with district authorities to provide assistance and relief measures.