Delhi Faces 45 Degrees Celsius Heatwave as Urban Heat Island Effect Intensifies

Delhi and the National Capital Region are under a yellow heatwave alert with temperatures forecast to reach 45 degrees Celsius in isolated pockets, while environmental campaigners claim that densely paved neighbourhoods in Ghaziabad recorded surface temperatures as high as 50 degrees Celsius. The India Meteorological Department issued the alert for May 19 and 20, 2026, following Delhi's hottest day of the season on May 18.

Safdarjung, Delhi's base weather station, logged a maximum temperature of 43.4 degrees Celsius on May 18, 2026, about three degrees above normal. Ridge and Ayanagar weather stations recorded temperatures above 44 degrees Celsius on the same day. The IMD forecast a maximum temperature range of 43 to 45 degrees Celsius over the heatwave period, with minimum temperatures expected to remain around 26 degrees Celsius, limiting overnight recovery for residents without cooling.

Environmental campaigners highlighted the urban heat island effect as a multiplying factor in dense, concrete-heavy localities. They argue that official weather station readings, typically located in relatively open areas, understate the temperatures experienced by residents in built-up urban zones where impervious surfaces absorb and retain solar heat. The claim of 50-degree surface temperatures in Ghaziabad, while based on campaigner monitoring rather than official instrumentation, reflects a growing recognition that urban planning choices have serious public health consequences.

Health authorities have advised residents to avoid outdoor activity during peak heat hours, stay hydrated and seek cooling centres if necessary. The heatwave comes amid broader concerns about Delhi's long-term warming trajectory, with climate scientists warning that urban heat islands could make parts of the NCR significantly hotter than surrounding areas within the next decade. Expanding green cover, introducing heat-reflective surfaces and enforcing construction standards that reduce heat retention are among the measures recommended.

Key figure — 43.4 degrees Celsius recorded at Safdarjung on May 18, 2026