Monsoon makes earliest onset over Mumbai in 75 years; red alert in Maharashtra, Karnataka districts

The southwest monsoon continued its swift advance across the Indian subcontinent, marking an exceptionally early onset over Mumbai on Monday.

IMD officials said the onset of southwest monsoon over Mumbai is the earliest arrival of rains in the country's financial capital in 75 years.

The normal date for monsoon's arrival in Mumbai is June 11.

"Southwest monsoon made its onset over Mumbai on May 26. This is the earliest onset in the last 75 years," India Meteorological Department (IMD) scientist Sushma Nair said.

Nair said the southwest monsoon arrived in Mumbai on May 29 in 1956. It arrived on the same date in 1962 and 1971.

The monsoon also reached Pune during the day.

According to the IMD, the southwest monsoon has now advanced further into several parts of central Arabian Sea, Maharashtra (including Mumbai), Karnataka (including Bengaluru), the remaining parts of Tamil Nadu, and parts of Telangana and Andhra Pradesh. It has also covered more areas in the west-central and north Bay of Bengal and reached the remaining parts of Mizoram, as well as the entire states of Tripura, Manipur, Nagaland, and Arunachal Pradesh.

Conditions remain favourable for further advancement over more regions of Maharashtra, the remaining parts of Karnataka, Telangana, Andhra Pradesh, the Bay of Bengal, northeastern states, and parts of sub-Himalayan West Bengal and Sikkim in the next three days.

Monsoon reaches Maharashtra early for first time in 35 years

The IMD said that the monsoon's arrival in Maharashtra on Sunday marked the earliest onset over the state in 35 years. Historically, the southwest monsoon reaches Kerala by June 1 and Mumbai by June 11. This year, the monsoon arrived in Kerala on May 24, its earliest onset since 2009.

M Rajeevan, monsoon expert and former Secretary of the Ministry of Earth Sciences, noted that early onset with wide coverage is not unusual. “In 1971, monsoon at the time of onset covered a larger area in Karnataka and parts of Maharashtra. Present active monsoon conditions will continue at least till June 2 and will help to advance monsoon into Maharashtra and eastern parts of the country,” he said.

Red alert in Mumbai

The IMD has issued warnings of continued rainfall activity in Maharashtra over the next 4–5 days. A well-marked low-pressure area over south Madhya Maharashtra and adjoining areas has now weakened but continues to drive intense weather patterns across the region.

Rainfall, ranging from fairly widespread to very heavy, is expected in Konkan, Madhya Maharashtra, and Marathwada through May 30. Isolated places in Konkan and adjoining areas of Madhya Maharashtra are likely to witness extremely heavy rainfall on May 26–27. Thunderstorms with gusty winds (50–60 kmph), lightning, and heavy showers are predicted across the state through May 28.

Extremely heavy rainfall may occur in Kerala, Konkan (including Mumbai), the ghat areas of Madhya Maharashtra and Karnataka on May 26–27, and over the ghat areas of Tamil Nadu on May 26.

The India Meteorological Department (IMD) has issued a red alert in several districts of Maharashtra, including Mumbai City, Thane, and Raigad.

The red alert for coastal Karnataka will also remain in force for the next five days.

A red alert indicates extremely heavy rainfall of over 20 cm in 24 hours.