Explained: Why India's Monsoons Are Now Deadlier And More Unpredictable

Himachal Pradesh is once again in the grip of severe monsoon, with over 260 roads blocked - 176 of them in Mandi district - after days of relentless rain. The India Meteorological Department has issued a red alert for extremely heavy rainfall in Kangra, Sirmaur and Mandi districts and in many other states of the country. At least 69 people have died and 37 are missing following cloudbursts and landslides this week alone. Last year, more than 550 people were killed during the monsoon season in the state.

Experts attribute the increasing frequency and severity of such events to climate change, which is altering monsoon behaviour in India. These shifts threaten agriculture, water systems, and disaster preparedness nationwide, making monsoons more dangerous and unpredictable than ever.

According to government reports, over the 1901-2018 period, the Indian surface air temperature rose by approximately 0.7 degrees Celsius, while tropical Indian Ocean sea-surface temperatures climbed by around 1 degree Celsius between 1951 and 2015. As warmer air can hold more moisture-about 7 % per 1 degree Celsius, this results in more intense rainfall events.

Regional rainfall trends now reveal a paradox: May rainfall in North India has surged by nearly 50% since 1950, prolonging humid pre-monsoon conditions, but the core monsoon season (June-September) is weakening, producing less overall rain with higher temperatures.

According to the India Meteorological Department, studies show that seasonal rainfall has declined approximately 6% in the last 50 years, with central India experiencing fewer moderate rain days and more frequent extreme events, up to 75% more heavy-rain days (>150 mm/day).

On a detailed level, 55% of India's sub-districts (tehsils) saw monsoon rainfall increase over the past decade, driven chiefly by short-duration heavy downpours, while 11 % experienced declines-especially in agriculture-dependent zones like the Indo-Gangetic plain. Furthermore, roughly 48 % of tehsils recorded higher rainfall in October, hinting at a delayed monsoon withdrawal, according to a Council on Energy, Environment and Water (CEEW) report.

How has the monsoon pattern changed in India?

According to CEEW, the natural variability of Indian monsoons is further influenced by climate change. Traditionally monsoon-rich regions like Northeast India, the Indo-Gangetic plains, and the Indian Himalayan region experienced a decrease in the past decade. Conversely, traditionally drier areas, including Rajasthan, Gujarat, central Maharashtra, and Tamil Nadu, witnessed an increase in southwest monsoon rainfall. The northeast monsoon intensified in Tamil Nadu, and states such as Odisha and West Bengal on the east coast, as well as Maharashtra and Goa on the west coast, observed heightened October to December rainfall.

What's Driving India's Changing Monsoon Patterns?

India's monsoon is becoming increasingly unpredictable due to several key factors. Rainfall is now more erratic, with intense downpours followed by dry spells, and the monsoon's onset is often delayed, impacting agriculture. Some regions face drought-like conditions while others receive excessive rain. Climate change plays a major role; Indian Ocean warming, global atmospheric shifts, and urbanisation are altering monsoon behaviour. To adapt, India needs better forecasting systems, sustainable land use practices like afforestation, and efficient water storage and distribution infrastructure to manage rainfall variability and ensure long-term resilience.