The Southwest Monsoon of 2025 has left an indelible mark on India, with 45% of the country drenched in extreme rainfall, triggering devastating floods, landslides, and over 1,500 lives lost.
As the season concluded with 108% of the long-period average (LPA) rainfall, experts point to climate change-not El Nino or La Nina-as the primary force behind the intensifying deluge, as per an analysis by Climate Trends. This year marks the second consecutive monsoon with above-normal rainfall, a trend that underscores the growing influence of global warming on India's weather patterns.
A Wetter Monsoon in a Warming World
The 2025 monsoon, spanning June to September, saw unprecedented rainfall across vast swathes of India. According to the India Meteorological Department (IMD), 19 of 36 meteorological subdivisions (46% of India's landmass) recorded normal rainfall, while 12 subdivisions (35%) experienced excess rainfall, and two subdivisions (10%) saw large excess rainfall. Only three subdivisions, covering 9% of the country, faced deficient rainfall. Of India's 727 districts, 328 recorded normal rainfall, 186 saw excess, 67 reported large excess, and 134 faced deficits.
"Monsoon seasons are not the same anymore," said KJ Ramesh, former Director General of the IMD. "Global warming has become the biggest driver of the monsoon now. The number of rainy days has decreased, but the quantum of rainfall per event has increased significantly."
Over the past decade (2016-2025), five years have registered above-normal rainfall, two recorded normal, and three saw below-normal levels. This year's 108% LPA rainfall solidifies a trend of wetter monsoons, with 14 of the 18 monsoon weeks in 2025 delivering excess or large excess rainfall.
Regional Rainfall: Winners and Losers
Northwest India emerged as the top performer, recording 27% excess rainfall-the highest since 2001. Ladakh led with a staggering 342% surplus, followed by Rajasthan (60-70% excess). Central India, the core monsoon zone, also performed strongly, with Gujarat (+25%), Madhya Pradesh, and Maharashtra leading the charge.
In stark contrast, East and Northeast India struggled with a 20% rainfall deficit, marking the region's second-lowest monsoon rainfall since 1901. Assam, Arunachal Pradesh, and Bihar were among the worst hit, with 22 of Assam's 34 districts, 11 of Arunachal's 15, and 25 of Bihar's 38 reporting deficits. The West Coast, a key monsoon contributor, saw mixed results: Konkan and Goa thrived, but Kerala recorded a 13% deficit, with Wayanad (-36%) and Idukki (-35%) facing significant shortfalls.
A Surge in Extreme Weather
Monsoon 2025 unleashed 2,277 flood and heavy rainfall events, claiming 1,528 lives. Madhya Pradesh reported the highest toll at 290 deaths, followed by Uttar Pradesh (201), Himachal Pradesh (141), and Jammu & Kashmir (139). August was the most flood-intensive month, with 28 of the 59 Highest Flood Level (HFL) breaches recorded across nine river basins. The Ganga basin alone accounted for 32 incidents, including 10 in the Yamuna.
"Extreme rainfall events have tripled since 1950," noted Mahesh Palawat, Vice President of Meteorology and Climate Change at Skymet Weather. "Low-pressure systems are lingering longer over land, fueled by continuous moisture from warmer seas, leading to cloudburst-like conditions."
Climate Change: The Monsoon's New Master
Experts attribute the monsoon's intensification to a cocktail of climate change-driven factors:
1. Warmer Seas, More Moisture: Rising sea surface temperatures in the Arabian Sea and Bay of Bengal have increased evaporation, loading the atmosphere with moisture. "The Indian Ocean's warming is enhancing cross-equatorial monsoonal flow, carrying more water vapor to fuel intense rainfall," Palawat explained.
2. Shifting Western Disturbances: Traditionally a winter phenomenon, Western Disturbances (WDs) are now influencing summer monsoons due to a northward shift of the subtropical westerly jet (SWJ). "WDs are pulling the monsoon trough northward, triggering heavy precipitation in Northwest India," said Professor A.P. Dimri, Director of the Indian Institute of Geomagnetism.
3. Middle East Warming: A recent study links a 46% increase in Northwest India's rainfall to rapid warming in the Middle East, which destabilizes the atmosphere and drives moisture northward.
4. Himalayan Vulnerability: Accelerating glacial melt and permafrost thaw in the Himalayas, warming at three times the global average, have amplified flooding risks. "Glacial retreat isn't the primary cause of flash floods, but it significantly amplifies them," said Dr. Argha Banerjee, a glaciologist at IISER Pune.
A Nation Under Water
The 59 HFL breaches across nine river basins underscore the monsoon's ferocity. The Ganga basin bore the brunt, followed by the Indus (15 incidents) and Krishna (4). August and September were particularly brutal, with landslides and floods devastating northern states like Himachal Pradesh and Jammu & Kashmir.
"Monsoon 2025 was a wake-up call," said Dr. Ramesh. "Rainfall patterns are shifting-more rain in Rajasthan and Gujarat, less in Uttar Pradesh and Bihar due to aerosol pollution. Northeast India's decline is alarming. We must adapt to these changes."
Looking Ahead: Adapting to a New Normal
As climate change rewrites India's monsoon playbook, experts urge proactive adaptation. Urban planning, flood management, and sustainable land use are critical to mitigating the impacts of increasingly erratic rainfall. With the Indian Ocean projected to warm further, the monsoon's intensity is likely to escalate, challenging India's resilience.
"The data is clear," concluded Professor Dimri. "From glacial melt to shifting wind patterns, climate change is amplifying the monsoon's extremes. We're seeing the consequences now-India must prepare for a future of wetter, wilder monsoons."
