Climate Change Transforms India's Monsoon: 45% of Country Faces Extreme Rainfall in 2025

"Monsoon seasons are not the same anymore," said KJ Ramesh, former Director General of the IMD (File)

The Southwest Monsoon of 2025 has dramatically impacted India, with 45% of the country experiencing extreme rainfall, leading to devastating floods, landslides, and over 1,500 fatalities.

Concluding with 108% of the long-period average rainfall, climate experts identify global warming—not El Nino or La Nina—as the primary driver behind these intensifying weather patterns, according to Climate Trends analysis. This represents the second consecutive year of above-normal monsoon rainfall, highlighting climate change's growing influence on India's weather systems.

The 2025 monsoon season, from June through September, delivered unprecedented precipitation across large portions of India. The India Meteorological Department (IMD) reports that 19 of 36 meteorological subdivisions (46% of India's landmass) received normal rainfall, while 12 subdivisions (35%) experienced excess rainfall, and two subdivisions (10%) recorded large excess rainfall. Only three subdivisions, representing 9% of the country, faced rainfall deficits. Among India's 727 districts, 328 recorded normal rainfall, 186 experienced excess, 67 saw large excess, and 134 faced deficiencies.

KJ Ramesh, former Director General of the IMD, observed: "Monsoon seasons are not the same anymore. 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 levels, and three experienced below-normal precipitation. This year's 108% LPA rainfall reinforces the trend toward wetter monsoons, with 14 of the 18 monsoon weeks in 2025 delivering excess or large excess rainfall.

Northwest India emerged as the top performer, recording 27% excess rainfall—the highest since 2001. Ladakh led with an astounding 342% surplus, followed by Rajasthan (60-70% excess). Central India, the core monsoon zone, also performed strongly, with Gujarat (+25%), Madhya Pradesh, and Maharashtra receiving substantial precipitation.

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 affected, with 22 of Assam's 34 districts, 11 of Arunachal's 15, and 25 of Bihar's 38 reporting deficits. The West Coast, traditionally a key monsoon contributor, saw mixed results: Konkan and Goa thrived, while Kerala recorded a 13% deficit, with Wayanad (-36%) and Idukki (-35%) facing significant shortfalls.

The 2025 monsoon unleashed 2,277 flood and heavy rainfall events, claiming 1,528 lives. Madhya Pradesh reported the highest toll with 290 deaths, followed by Uttar Pradesh (201), Himachal Pradesh (141), and Jammu & Kashmir (139). August proved the most flood-intensive month, with 28 of the 59 Highest Flood Level 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 scientists attribute the monsoon's intensification to several 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 are now influencing summer monsoons due to a northward shift of the subtropical westerly jet. "Western Disturbances 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.

The 59 Highest Flood Level breaches across nine river basins underscore the monsoon's severity. The Ganga basin experienced the most incidents, followed by the Indus (15) and Krishna (4). August and September were particularly devastating, with landslides and floods ravaging 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."

As climate change continues to transform India's monsoon dynamics, experts emphasize the need for proactive adaptation strategies. Urban planning, flood management systems, and sustainable land use practices will be crucial for mitigating the impacts of increasingly unpredictable rainfall patterns. With the Indian Ocean projected to warm further, monsoon intensity is likely to escalate, presenting significant challenges to India's resilience and adaptive capacity.

"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."