Mumbai woke up to a rain-soaked Wednesday as intense overnight showers swept across the city and nearby areas after the southwest monsoon finally made its entry into the financial capital.

With rainfall continuing through the night in several parts of the Mumbai Metropolitan Region, the India Meteorological Department (IMD) issued a red alert for Mumbai and Palghar at around 4 am on Wednesday. The warning, valid for three hours, cautioned residents about thunderstorms, lightning, very heavy rainfall and gusty winds reaching 40 to 60 kmph.

By 7 am, the weather warning was scaled down to an orange alert for the next three hours, though the IMD said moderate to heavy spells of rain were still likely in Mumbai, Thane, Palghar, Raigad and Sindhudurg.

The heavy showers left several low-lying parts of Mumbai flooded by morning. Waterlogging was reported from multiple neighbourhoods, with visuals showing roads submerged in areas such as King’s Circle in Matunga, where trucks and other vehicles were seen pushing through pooled water. Residential pockets in Dadar’s Hindu Colony also witnessed flooding after the relentless rain.

The monsoon reached Mumbai on Tuesday, arriving 13 days later than its usual onset date of June 10. In an official update, the IMD said the southwest monsoon had advanced further into more parts of Maharashtra, including Mumbai, as well as additional areas of Telangana, Odisha, Chhattisgarh, Jharkhand and Bihar.

Amid the downpour, a retaining wall beside a residential building in Vikhroli West collapsed late Tuesday night, adding to concerns over rain-related damage in the city.

One of Mumbai’s busiest transit points, Dadar station — where the Central and Western suburban railway corridors meet — also saw water accumulation on Wednesday morning as the rain continued to batter the city.

According to data from the Brihanmumbai Municipal Corporation (BMC), Mumbai recorded over 300 mm of rainfall in the 24-hour period between 8 am Tuesday and 8 am Wednesday. Under IMD classification, rainfall exceeding 204.4 mm in a day falls in the “extremely heavy” category.

Although the monsoon arrived late this year, it was not the latest onset on record. IMD data shows the rains reached Mumbai on June 25 in 2023, while the most delayed arrivals were recorded in 1958 and 1974, when the monsoon began on June 28.

The BMC said all major subways were open on Tuesday and suburban train services, along with BEST buses, continued to run normally. However, persistent rainfall did affect road traffic in some stretches. The Andheri subway had to be shut on Wednesday after flooding caused by overnight rain. Videos from the area showed commuters walking through knee-deep water late Tuesday night.

Rainfall figures released by the civic body showed that between 8 am and 7 pm on Tuesday, Nair Hospital recorded the highest rainfall in the city at 78.96 mm. NM Joshi Marg-Lower Parel followed with 78.4 mm, while Parel TT received 72.63 mm.

In the suburbs, Malad Bus Depot logged 61.8 mm of rainfall, while Maharashtranagar in Mankhurd received 51.2 mm, according to the BMC.

The first major spell of monsoon rain has brought relief from the heat, but it has also exposed the city to the familiar challenges of flooding, waterlogged roads and traffic bottlenecks as the rainy season gains momentum.