Delhi’s subdued monsoon this year, despite early promise and widespread rainfall in surrounding regions, underscores the unique meteorological and urban challenges the capital faces. From June 1 to July 9, Delhi recorded nearly 25% less rainfall than normal, while India as a whole received 15% above-normal rainfall—a striking contrast that reveals how localised climate dynamics can diverge sharply from national patterns.
What Went Wrong in Delhi?
The India Meteorological Department (IMD) had forecast a favourable monsoon season for Delhi, especially following its early onset on June 29, two days ahead of schedule. However, those predictions did not materialise. The monsoon trough, which was expected to linger over the capital and deliver sustained showers, shifted northward within hours, settling near Chandigarh, about 150 km away, drastically reducing rainfall potential for Delhi.
Compounding the situation, Western Disturbances—a key secondary weather driver in North India—also missed Delhi, travelling further north than usual. Their altered path meant that even these periodic systems, which often rejuvenate monsoon spells or bring supplemental rain, failed to benefit the city.
Meanwhile, Neighbouring States Thrived
While Delhi remained relatively dry:
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Rajasthan surged with a 121% rainfall surplus.
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Haryana received 32% above-normal rain.
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Punjab and Uttarakhand also saw 15% and 22% surpluses, respectively.
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Even Uttar Pradesh, which often mirrors Delhi’s weather patterns, received a 1% increase.
This regional contrast highlights how small positional shifts in monsoon systems can create starkly different rainfall outcomes over relatively short distances.
The Urban Heat Island (UHI) Effect: A Key Local Factor
Delhi’s extensive urbanisation and concretisation have created an intense Urban Heat Island (UHI) effect. In areas like South and East Delhi, temperatures can be 2°C to 9°C higher than surrounding rural regions. This concentrated heat distorts local wind and atmospheric convection patterns, weakening the very cloud formation and uplift mechanisms that enable rainfall.
The result: even when broader monsoon systems are favourable, rainfall can be suppressed or redirected due to localized warming—especially over the city’s core.
The Complexity of Forecasting for a City Like Delhi
As Dr. R.K. Jenamani of the IMD explains, Delhi’s rainfall outcomes are shaped by a delicate balance of:
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Monsoon trough dynamics
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Western Disturbances
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UHI-induced local temperature anomalies
The spatial heterogeneity within the city further complicates matters—where areas like Najafgarh might receive moderate showers, central parts of Delhi experience only scattered drizzles.
Broader Implications
Delhi’s monsoon shortfall isn’t just a statistical anomaly—it has serious implications:
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Water scarcity could worsen as groundwater and reservoir replenishment lags.
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Heat stress and energy demands are likely to rise due to sustained high urban temperatures.
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Urban planning and climate resilience need to incorporate microclimate-sensitive strategies.
The Way Forward
This episode highlights the urgent need for:
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Finer-resolution weather models that incorporate urban microclimates.
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Better integration of real-time environmental monitoring (like urban surface temperatures and heat flux data).
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Smarter infrastructure planning that mitigates UHI through green spaces, reflective surfaces, and less dense construction.
