BRIEF: Gridlike Cities Are Hotter

(Inside Science) -- The gridlike street network in Manhattan might be a breeze to navigate, but it actually makes the city physically hotter. Researchers from the Massachusetts Institute of Technology investigated how the arrangement of a city’s streets and buildings can affect how much hotter a city stays through the night compared to surrounding rural areas. They found that cities with gridlike street networks stay hotter than ones with more chaotic road designs. The researchers published their findings in the journal Physical Review Letters.

Cities are generally warmer than nearby natural areas -- an effect called an urban heat island. It is partly due to building materials such as concrete that store up heat during the day and radiate it during the night, and partly due to extra heat generated by human activities. These combined effects can cause city temperatures to rise as much as an extra 10 degrees Fahrenheit in places like Phoenix, Arizona . The MIT researchers have now found the city plan itself can be another culprit.

By combining Google Maps and historic weather data from 47 cities around the world, the researchers found the arrangement of a city’s streets and buildings plays a significant role in keeping a city hotter during nighttime.

City planners can use this information to better design future urban developments or perhaps even retrofit existing cities to adapt to the local climate.