델리의 날씨가 43도인데 왜 더 뜨거워 보일까?

Delhi had a very hot day. The air temperature was 43.5 degrees Celsius. But many people said it felt much hotter. Why?

Scientists wanted to find the answer. They took special cameras to the city. These cameras show how hot things really are. The cameras can see surface temperature. Surface temperature is the heat on objects.

They measured many things. They checked buildings. They measured the ground. They looked at cars. They examined trees and grass.

The results were surprising. Many surfaces were much hotter than the air. Dark roads were very hot. Black cars were extremely hot. Concrete buildings became very hot too. Even light-colored buildings got hot in the sun. But trees and grass stayed cooler.

This explains why it felt hotter. When you stand on a hot road, heat comes from below. When you stand near a hot building, heat comes from the side. The hot air comes from above. All this heat together makes the body feel very hot. But thermometers only measure air temperature.

Cities have many hard surfaces. Roads are black. Buildings are concrete. Cars are metal. These materials hold heat. Trees and plants do not hold as much heat. They give off cool air instead.

This is important information. It helps cities plan for hot weather. Cities can plant more trees. They can paint roads with light colors. They can use cooler materials for buildings. These changes help people feel more comfortable.

Inspired by reporting from BBC News.