New Orleans Ranks As Worst Heat Island In U.S.

New Orleans is one of the major heat islands in America, according to, a new study by the Climate Central research group.

The research shows that on average the city is about 9 degrees hotter than the surrounding countryside. Some parts of the city rise to 16 degrees hotter.

New Orleans had the highest score, followed by Newark, NJ, New York City, Houston and San Francisco.

Researchers looked at factors that cause a heat island effect, namely buildings and pavement that cause cities to be hotter than their outer areas.


Climate Central

Climate Central calculated heat retention by looking at albedo – that’s how well the city reflects solar energy. They also rated the green space, which cools a city, the population density – the closer, the hotter; and building height – tall buildings have a cooling effect.

Many New Orleans buildings have black tar shingles and many of the roads are asphalt, both of which help a city retain heat. Cities with lighter roofs and light-colored concrete pavement, such as Phoenix, absorb less heat.

Tall buildings cool cities, and New Orleans doesn’t have much of them. Trees and parks also have a cooling effect, as do permeable surfaces, such as mulched areas and lawns, that absorb rather than trap heat. The city scored low on all points.

Climate science director Andrew Pershing said New Orleans could cool down if the city built more parks, planted more trees and encouraged people to use lighter roofing materials.

“Think about how much asphalt pavement you have that will absorb a lot of heat, versus light-colored concrete or light-colored buildings. Think of your roofing materials, that will change the color of a city and it will absorb more heat,” he said.

“The big factor in New Orleans is the ‘albedo’. New Orleans has a lot of dark-colored roofs and pavement, which makes the city want to warm up more.”

Recently updated city code discourages tree felling and encourages the use of green infrastructure.

Increased heat can have serious health consequences, such as heat stress, and can cause dangerous ozone levels. Higher summer temperatures also put a strain on the electrical grid as the use of air conditioners soars.

Support for the Coastal Desk comes from the Walton Family Foundation, the Greater New Orleans Foundation, and local listeners.

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