Delhi has recorded its wettest May ever, marking a significant departure from the typical weather patterns of the season. The city surpassed all previous rainfall records since 1901, accumulating 186.4 mm of rain by May 25, 2025. This broke the previous record of 165 mm set in May 2008. The unusual weather brought respite from the intense summer heat but also caused significant disruptions due to waterlogging and infrastructural damage.
The record-breaking rainfall was largely attributed to a powerful thunderstorm that struck the city in the early hours of Sunday, delivering 81.4 mm of rain within just a few hours. This downpour, classified as "heavy" by the India Meteorological Department (IMD), contributed significantly to the month's cumulative rainfall. The storm was accompanied by strong gusty winds, with speeds peaking at 82 kmph, leading to widespread waterlogging, uprooted trees, and disruptions at Indira Gandhi International Airport.
The IMD had issued a red alert prior to the storm, warning of approaching thunderstorms and strong winds. The storm, which hit between approximately 1:15 AM and 2:30 AM on May 25, caused considerable chaos across Delhi and the National Capital Region (NCR). Numerous roads and underpasses were flooded, and over 49 flights were either delayed or diverted due to the adverse weather conditions. A section of the external tensile fabric at Terminal 1 of Delhi Airport was also impacted due to the heavy rain.
The intense weather conditions were attributed to a combination of factors. According to weather officials, the interaction between moist southeasterly winds and dry westerlies played a crucial role. Additionally, three active weather systems further intensified the storm: a western disturbance over north Punjab and Jammu and Kashmir, and two upper air cyclonic circulations—one over northwest Uttar Pradesh and north Haryana, and another over west Rajasthan.
The heavy rainfall led to a dramatic drop in temperatures. At the Safdarjung observatory, the city's primary weather station, the mercury plunged by 10 degrees Celsius in just 75 minutes, dropping from 31°C to 21°C. Similar temperature drops were observed across other weather stations in the city, providing immediate relief from the heat.
While the heavy rain has provided a temporary respite from the heat, the IMD has forecast a gradual increase in temperatures in the coming days, with daytime temperatures expected to reach 40 degrees Celsius by May 28. The weather department has predicted partly cloudy skies in the short term, but this relief is not expected to last.
The record-breaking rainfall in May follows a pattern of intense weather events in Delhi. Earlier in the month, on May 2, the city recorded 77 mm of rainfall, which was then the second-highest 24-hour rainfall total for May. The long-term average rainfall for May in Delhi is typically around 30.7 mm, making this year's 186.4 mm a significant anomaly. In light of the recent events, the anti-drone system is set to be installed in Taj Mahal complex to avoid any unfortunate events.
The events of May 2025 highlight the increasing frequency and intensity of extreme weather events. The city's infrastructure struggled to cope with the heavy downpour, leading to widespread disruption and inconvenience for residents. The IMD has forecast intermittent light rain and thunderstorms for the remainder of the week, accompanied by winds of up to 50 kmph.
