Monsoon 2025: Why is India seeing early monsoon showers? Know reason behind Mumbai, Kerala floods in May

Several Indian states, including Maharashtra and Kerala, are experiencing an unusually early onset of the monsoon this year. The sudden and heavy rainfall has already disrupted life in Mumbai, which came to a standstill on Monday, 26 May, due to widespread waterlogging and transport delays.

According to the India Meteorological Department (IMD), the monsoon arrived in Maharashtra on Sunday, 25 May, ten days earlier than its typical date of 5 June. This is the earliest monsoon arrival in the state since 1990, and for Mumbai, it marks the earliest onset in 35 years.

The downpour began overnight and continued into the morning, affecting railways, flights, and road traffic. Low-lying areas such as King’s Circle, Mantralaya, Dadar TT East, Parel TT, Kalachowki, Chinchpokli, and Dadar station were submerged, causing major traffic jams. Mumbai’s Colaba observatory recorded 135 mm of rainfall, while Santacruz recorded 33 mm by 8:30 am. The IMD issued a yellow alert for the city till Wednesday, warning of continued rain and strong winds up to 40 kmph.

Flights were also affected. SpiceJet and Air India advised passengers to check their flight status before leaving for the airport due to delays caused by the poor weather.

Meanwhile, Kerala, which usually sees the monsoon by 1 June, experienced its first showers on 24 May, the earliest since 2009. The rain hit hard in the state’s northern districts, uprooting trees, damaging homes, and flooding farmland. Several tribal families in Wayanad had to be moved to relief camps.

The monsoon has also reached parts of Karnataka, Goa, Lakshadweep, and northeastern states like Manipur, Mizoram, and Nagaland. The quick spread has raised questions about what triggered such an early onset.

Experts point to favourable atmospheric and oceanic conditions. The Madden-Julian Oscillation (MJO), the Mascarene High, and the monsoon trough all played a role. The MJO, which affects cloud and rainfall patterns across the tropics, supports strong monsoon winds. The Mascarene High, a high-pressure zone in the south Indian Ocean, helps push moist winds towards India. The monsoon trough, a low-pressure area stretching from the Arabian Sea to the Bay of Bengal, also aids rainfall development.

Additionally, the absence of strong El Nino or La Nina patterns (known as neutral ENSO conditions) and reduced snow cover over the Himalayas may have contributed to the early rains.

The early monsoon could prove beneficial for agriculture, as nearly 70% of India’s annual rainfall occurs during this season. Few experts suggest that early rains and high soil moisture could allow farmers to sow summer crops earlier, possibly leading to better crop yields. This could support farming, fisheries, and livestock in several states.

Overall, while the early onset has caused disruption in some areas, it also brings hope for a productive agricultural season.