Cloudy with a chance of error: Why IMD is struggling to get Delhi's rain right

India Today

09-07-2025

This monsoon season, Delhi appears rather unlucky when it comes to rainfall. Although the skies over the national capital have often been filled with clouds, the expected precipitation has largely eluded the city.Unlike neighboring states, which have enjoyed abundant rains, Delhi has experienced a significant deficit, receiving almost 25% less rainfall than usual from June 1 to July 9.Contrastingly, this monsoon has been overall favourable for India. The country has recorded about 15% more rainfall than the normal levels during the initial 40 days of the season.advertisement
States surrounding Delhi have benefited from this surplus. Haryana noted an impressive 32% increase in rainfall, Punjab saw 15% above-normal precipitation, Rajasthan led with an astonishing 121% increase, and Uttarakhand recorded 22% more rain. Even Uttar Pradesh managed a slight rise of 1%, making Delhi's deficit all the more notable.
Delhi's rainfall is governed by multiple large climatic systems. (Photo: PTI)
Will Delhi get good rainfall in the days to come?The India Meteorological Department's (IMD) prediction for Delhi's monsoon rainfall after the onset on June 29 largely went wrong. Though the monsoon arrived two days ahead of schedule, expectations of heavy rain across the city were not met.The IMD had forecast significant rainfall from July 6 onwards, anticipating that the monsoon trough, which had moved northward from central India, would linger over Delhi and bring consistent showers.However, as explained by Dr. R K Jenamani, a senior scientist at IMD, "the active monsoon trough remained over Delhi for only a few hours during the last weekend before shifting northwards toward Punjab. Currently, the trough is positioned roughly 150 kilometers north of Delhi near Chandigarh."This shift has significantly reduced the chances of substantial rainfall in Delhi in the coming days. As a result, core parts of Delhi experienced only light and scattered showers, while some outer regions, like Najafgarh, received moderate rain.This gap between forecasted and actual rainfall shows the challenges in predicting monsoon behaviour in densely populated urban areas.
States surrounding Delhi have benefited from this surplus. (Photo: PTI)
Scanty rainfall in DelhiDelhi, one of India's most densely populated urban centers, has witnessed extensive concretization over the years.This rapid urbanisation has significantly contributed to the Urban Heat Island (UHI) effect, where built-up areas experience considerably higher temperatures than their rural surroundings.advertisementIn Delhi, particularly in the heavily developed South and East regions, temperatures can be 2C to 9C hotter due to UHI. This temperature disparity directly influences local weather, especially precipitation patterns.The UHI effect alters convection and atmospheric dynamics over the city. Warmer urban surfaces heat the air above, affecting local wind patterns and cloud formation. These changes can suppress rainfall over dense urban zones, as convection currents weaken or shift, leading to reduced precipitation.The phenomenon results in a complex interaction of atmospheric variables that disturb the usual cycle of rainfall, aggravating water scarcity issues in the city.However, Delhi's rainfall is also governed by other larger climatic systems. According to the India Meteorological Department (IMD), rainfall depends on the convergence of several factors.For instance, the monsoon trough in 2023 remained active for a brief period, limiting overall monsoon rainfall. Furthermore, Western Disturbances (WD)—frontal weather systems traveling from the Mediterranean—play a vital role in northern India's weather, including Delhi's precipitation.Dr. R K Jenamani, meteorologist and expert, explains that most Western Disturbances this year passed to the north of Delhi, failing to bring significant rain to the capital. Their northward track, combined with short-lived monsoon trough activity, led to a rainfall deficit. advertisementThus, while UHI intensifies local warming and modifies convection, India's complex monsoon system and Western Disturbances importantly regulate the amount and timing of rainfall in Delhi.Hence, there are challenges faced by meteorological departments in making precise monsoon forecasts for metropolitan areas like Delhi, where climatic conditions can vary drastically over short distances.It also highlights the need for continuous improvements in weather prediction models that can account for the complex interplay of local atmospheric and environmental factors.- EndsMust Watch