Delhi roads are burning at 65°C. So, why do weather apps show just 42°C?

The Sun is not just hot in Delhi right now. It is cooking the city from the ground up. As temperatures across the national capital and large parts of North India hover between 40°C and 45°C, stepping outdoors has become an exercise in endurance for millions of residents. But the numbers on your weather app tell only half the story. Nand Nagri, a dense residential settlement in East Delhi, has revealed a far more alarming reality. Read Full Story WHEN THE ROAD IS HOTTER THAN YOUR OVEN Using a thermal camera and a handheld temperature meter provided by Greenpeace India, we measured actual surface temperatures at multiple points in the area. The results were startling. Under direct sunlight, the surface temperature of roads and parked vehicles exceeded 65°C. A thermal camera works by detecting infrared radiation, which is the invisible heat energy emitted by all objects, and converting it into a colour-coded visual image. Hotter surfaces glow red or white on screen; cooler ones appear blue or green. In this case, the tarmac was blazing. The thermal imaging device records over 65°C on an exposed road surface in East Delhi, while the shaded ground nearby registers nearly 20 degrees lower. The stark colour contrast illustrates just how dangerous unshaded urban surfaces can be during a heatwave. (Photo: India Today) Move just a few metres into the shade of a tree, however, and the reading dropped to around 40°C. That is a gap of nearly 20 degrees Celsius in the span of a few steps. The difference is not trivial. At 65°C, unprotected skin can suffer thermal burns within seconds. Children who play barefoot on such surfaces, and there are many in settlements like Nand Nagri, are especially vulnerable. THE GAP YOUR WEATHER APP DOES NOT SHOW YOU The team also measured air temperature using a handheld thermometer. While standing in direct sunlight, the device recorded 48°C. At the same moment, weather apps on mobile phones showed 42°C for the same location. That is a 6-degree gap between the official forecast and what a person actually experiences while standing outdoors. The reason for this discrepancy is straightforward. Official weather station readings are typically taken in the shade, at a standardised height of about 1.2 metres above the ground, away from heat-reflecting surfaces. Delhi roads are hitting 65°C but your weather app says 42°C. India Today's thermal camera ground report from Nand Nagri reveals the heat crisis your phone isn't showing you. (Photo: PTI) They represent ambient air temperature under controlled conditions. What people feel on a congested street, surrounded by concrete, metal, and vehicle exhaust, is considerably higher. Under tree cover, the air temperature dropped to approximately 42°C to 43°C, matching the app reading precisely. Trees cool the air through a process called evapotranspiration, where water absorbed through the roots is released as water vapour through the leaves. This evaporation draws heat out of the surrounding air, the same basic principle as sweating. Their canopy also blocks direct solar radiation from reaching the ground. THE HEAT DIARY OF NAND NAGRI Among the residents the team spoke to was Arshi, a political science student who lives in the settlement. She has been keeping what she calls a Heat Diary, a personal journal in which she records how extreme heat affects the daily lives of people around her. Power cuts that disrupt sleep. Children who cannot study because classrooms are unbearable. Elderly residents who cannot afford medical care when heat-related illness strikes. A handheld thermometer shows 48°C while a mobile weather app displays 42°C for the same location in Delhi, highlighting the significant gap between official forecasts and the heat people actually experience on the street. (Photo: India Today) Arshi pointed to a pattern she finds deeply unjust. Those who drive deforestation and industrial pollution, she noted, are largely insulated from its consequences. They live and work in air-conditioned spaces. The communities that bear the sharpest edge of rising temperatures are often those with the least power to change the conditions causing them. NO RELIEF IN SIGHT According to weather forecasts, temperatures across Delhi-NCR and North India are expected to remain above 40°C for at least another week, with no significant relief in the immediate forecast. This heatwave is not an anomaly. India's summers have been growing progressively hotter, a trend consistent with global climate projections. Rapid urban expansion has replaced vast stretches of green cover with concrete, asphalt, and glass, all materials that absorb heat during the day and radiate it back at night in what is known as the urban heat island effect. Delhi roads are hitting 65°C but your weather app says 42°C. (Photo: PTI) The consequences are being felt most acutely in densely packed low-income neighbourhoods where trees are sparse and open space is scarce. A single tree can reduce the loc