Much of U.S. Bakes as Some Cities Break Temperature Records

New York Times: There’s a reason heat waves feel hotter in New York City: Concrete. And here in the city, we have a lot of it.

Our buildings, roads and sidewalks absorb the heat from the sun and then release it, a process known as the “urban heat island effect.”

2023 study on the phenomenon reported that New York City, followed by Newark, had the highest urban heat island, or U.H.I., index average of about 8.5 degrees. This means that if the temperature is 90 degrees, it feels more like 98.5. Other cities with high U.H.I. numbers include Miami, Seattle, New Orleans, Detroit and Chicago, all of which have averages of around 8 degrees.

When the National Weather Service releases heat index predictions, which factor humidity with temperature readings, it takes into account the urban heat island component, said Dominic Ramunni, a meteorologist at the weather service. “The value is baked into our computer model,” he said.

“Baked” is the operative word this weekend for those in New York and Newark, who are looking at a heat index of right around 100 through Sunday.

But there is a way for cities to mitigate against the heat: By incorporating more green spaces into our urban landscapes, said Amy Chester, the managing director of Rebuild by Design, a resiliency nonprofit. Read more >>