On Sunday, June 28, at around 6:30 p.m., we took infrared images in Bolesławiec showing the temperature of various surfaces in the urban environment. The photographs clearly illustrate how important shade, greenery and the type of surface are during hot weather.
The highest temperatures were recorded by the camera on car bodies. Readings there reached almost 68 degrees Celsius. This is considerably higher than the ambient temperature perceived by people, but this is how surfaces exposed to the sun heat up: metal, asphalt, concrete and dark elements of buildings.
Cars and roads heat up the most
The images show that car bodies were among the hottest points in the frame. The surface temperature of the vehicles reached around 68 degrees Celsius. The road surface was approximately 50 degrees Celsius.
Similar readings appeared in another shot comparing the road with a green area. The asphalt surface was approximately 50 degrees Celsius, while the grass under the trees was noticeably cooler.
Such differences matter not only for pedestrians’ comfort. Heated surfaces continue to release heat long after sunset, which can make the city warmer than open or green areas.
The temperature was much lower under the trees
The coolest places in the photographs were under the trees. The camera showed approximately 34–35 degrees Celsius there. The grass in the shade of the trees measured around 33 degrees Celsius.
This shows how important trees are in the city. Their crowns limit the heating of surfaces, provide shade and lower surface temperatures. In this case, the difference between the road and the grass under the trees was approximately 17 degrees Celsius.
In practice, this means that the same street can be experienced completely differently depending on whether a pedestrian is walking along a sunny pavement, beside a heated road, or in the shade of trees.
The camera shows surface temperature, not a weather forecast
One of the photographs also shows apartment blocks and part of the sky. The indicated air temperature above the buildings, with the camera pointed upward, was approximately 17 degrees Celsius. However, this type of measurement should be treated with caution: a thermal imaging camera primarily shows radiation and the temperature of surfaces visible in the frame, not the conventional air temperature measured by a meteorological station.
The most important conclusion from the photographs concerns the differences between surfaces in the city. In sunny places, cars and asphalt heated up to very high levels, while areas shaded by trees were noticeably cooler.