Which factors influence the temperature of a city?

The density of buildings, their absorption of light and the presence of vegetation are all factors on which the temperatures reached in cities depend.

In fact, some cities try to reduce the temperature trapped within the road network through reflective building surfaces and vegetation-rich roofs.

Using formulas that physicists use in the study of condensed matter, a surprising discovery was also made.

As is also intuitively obvious, the less space separating buildings, the more heat is trapped by them.

The counter-intuitive discovery, however, is that the layout of buildings and streets also influences the temperature of a city.

Buildings arranged in square, regular grids, which have an orderly crystal-like structure, tend to trap heat mainly because they do not allow air to flow freely, and because a greater portion of space is occupied by infrastructure, which absorbs heat during the day and releases it at night.

Temperatures in such cities can be as much as 20 degrees higher than in surrounding rural areas. Examples include New York and Chicago.

In contrast, cities with more random and disorganized layouts, with an amorphous glass-like or chaotic liquid structure, are those that remain cooler, less able to trap heat. An example of the latter type is London.

The planning of a city would therefore benefit from adopting the most appropriate layout according to the latitude in which it is located, which not only makes it more liveable, but also reduces costs and emissions due to artificial climate regulation.