Earliest monsoon in 75 years breaks 107-year-old May rainfall record in Mumbai
Mumbai experienced its earliest monsoon onset in 75 years on May 26, 2025, leading to record-breaking rainfall that surpassed a 107-year-old May record at the Colaba observatory. The heavy rains caused widespread flooding, disrupting traffic and leading to power outages across the city.
Waterclogging in Mumbai after record-breaking rainfall on May 26, 2025. Credit: Tejaswini Singhal
Mumbai has recorded widespread rainfall on May 26 following the early onset of the Southwest Monsoon, which arrived 16 days ahead of the usual June 11 schedule.
Mumbai’s Colaba observatory recorded 295 mm (11.61 inches) of rain this month, the highest for May on record. This surpasses the previous record of 279.4 mm (11 inches) set in 1918.
Even during Cyclone Tauktae in May 2021, the station had recorded slightly less rain at 257.8 mm (10.15 inches) for the month of May. Meanwhile, Santacruz has received 197.8 mm(7.79 inches) of rain this month.
The India Meteorological Department’s (IMD) Colaba observatory measured 135.4 mm (5.33 inches) of rain in the 24-hour period ending at 08:30 local time (LT) on May 26.
Between 08:00 and 12:00 LT on May 26, parts of Mumbai witnessed thunderstorms with lightning, heavy rain, and gusty winds reaching speeds of 50 to 60 km/h (31 to 37 mph).
In the same timespan, according to IMD figures, Colaba recorded 105.2 mm (4.14 inches) of rain, Bandra received 68.5 mm (2.70 inches), Juhu Airport 63.5 mm (2.50 inches), Santacruz 55 mm (2.17 inches), Sion 53.5 mm (2.11 inches), Chembur 38.5 mm (1.52 inches), Vikhroli 37.5 mm (1.48 inches) and Mahalaxmi the lowest with 33.5 mm (1.32 inches).
Earliest onset of monsoon in last 75 years
“The Southwest Monsoon has advanced to Mumbai on May 26, against the normal date of advancement, June 11. Thus, the monsoon has arrived in Mumbai 16 days earlier than usual. This marks the earliest monsoon advancement over Mumbai during the period 2001–2025,” IMD said in a statement.
“This is the earliest onset in Mumbai in the last 75 years,” IMD scientist Sushma Nair said. Nair said southwest monsoon arrived in Mumbai on May 29 in 1956 and on the same date in 1962 and 1971.
Heavy rainfall cripples rail, metro, and road movement
The heavy rainfall and resulting waterlogging caused significant disruptions across Mumbai’s suburban railway and metro services.
On the Harbour Line, train services between Wadala and Chhatrapati Shivaji Maharaj Terminus (CSMT) were suspended due to severe water accumulation at Masjid Bunder station. On the Western Railway line, operations were interrupted between Churchgate and Marine Lines after a tree fell onto the overhead equipment, while the Central Railway services experienced major delays on the Kalyan–Kasara route due to waterlogging.
Additionally, Mumbai Metro Line 3 services were halted between Acharya Atre Chowk and Worli after water entered the underground station at Worli.
A section of road gave way at Kemp’s Corner after prolonged water accumulation. In central Mumbai, both King’s Circle and Hindmata junctions remained waterlogged. Andheri subway in the western suburbs is also rendered useless because of waterlogging.
Blocked and overflowing drains near roadways made conditions worse across multiple neighborhoods. Many airlines have also issued advisories because of poor visibility and water accumulation at the airport.
In total, six spots across the city reported waterlogging, while authorities responded to 18 short-circuit cases and five wall collapse incidents so far.
Emergency measures in place as weather expected to worsen
“All agencies, including BMC, Army, and Navy, are on high alert and coordinating their efforts. The Chief Minister and Disaster Management Minister are closely monitoring the situation. It is the government’s responsibility to ensure smooth operations,” Maharashtra Deputy Chief Minister Eknath Shinde said during his visit to the Disaster Management department.
IMD forecasts more rain and strong winds for the city, with Red Alert being in effect till Tuesday, May 27.
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