Climate Central analyzed how urban heat island intensity varies within 44 major U.S. cities that together account for nearly one-quarter of the total U.S. population. This analysis calculates the urban heat island (UHI) index for each census tract within a city to estimate how much hotter these areas are due to the characteristics of the built environment.

Maps show urban heat hot spots within each city—whether concentrated in the urban core (e.g., Indianapolis) or sprawling across a vast developed area (e.g., Detroit).