1 million Dallasites live on an urban heat island

Dallas is one of six U.S. cities where at least 1 million people are exposed to urban heat islands, parts of town where temperatures feel at least 8 degrees warmer than in parks or wooded parts of the city.

Why it matters: City leaders are investigating which Dallas neighborhoods are the hottest to see where more trees should be planted.

• Concrete urban settings can exacerbate an already hot day, while trees and vegetation have a cooling effect.

What they found: Urban heat islands increase the temperatures in 65 major U.S. cities home to 15% of the national population, Climate Central researchers shared in a recent analysis.

• That heat burden isn't equally shared. A study from Columbia University found that historically segregated neighborhoods experience higher temperatures compared to traditionally white areas.
• In Dallas, 81% of the population resides in areas with an urban heat index 8 degrees hotter than shaded parts of the city.

Of note: The Climate Central analysis only focused on Dallas and did not include other cities in the region, including Fort Worth.

Zoom out: In San Antonio, 88% of people are in areas with an urban heat index 8 degrees higher due to the built environment. This percentage places the city fifth among other cities in the analysis, trailing Detroit.

The intrigue: What keeps us cool is making the outdoors hotter. Air conditioning can add 20% more heat outside, per the Climate Central report.

How to cool: Cities can lower temperatures by planting "green roofs" with gardens or other foliage and adding trees, especially along streets.