Urban Heat Hot Spots

Climate Central analyzed 18,945 census tracts across 44 major U.S. cities, finding that 41 million people (approximately 55% of the analyzed population) live in areas where the urban heat island (UHI) effect increases temperatures by 8°F or more. The study identifies albedo, green space percentage, and population density as the primary drivers of this effect, with New York City exhibiting the highest average UHI index. The analysis categorizes cities by heat patterns—concentrated cores, diffused zones, or sprawling intensity—and highlights that structural inequities often lead to disproportionate heat exposure for people of color and low-income populations.

• Across the 44 analyzed U.S. cities, approximately 55% of the population (41 million people) reside in census tracts with a UHI index of 8°F or higher.
• Nine cities have at least 1 million residents exposed to a UHI index of 8°F or higher, including New York (7.1 million), Houston (4.2 million), and Los Angeles (3.2 million).
• New York City has the highest average UHI index both by area (8.6°F) and per capita (9.5°F), while Wichita has the lowest per capita average (7.2°F) and Las Vegas the lowest area-weighted average (5.8°F).
• The primary factors influencing the UHI index are albedo, the percentage of green space, and population density, with albedo having the most significant effect.
• Urban heat patterns vary by city: some have concentrated heat in the urban core (e.g., Indianapolis), some have diffused zones (e.g., Chicago), and others exhibit sprawling heat intensity (e.g., Detroit, New York City).
• Structural inequities contribute to disproportionate heat exposure; specifically, Black and African American individuals are 40% more likely than others to live in areas with the highest projected increases in extreme temperature related mortality under 2°C of global warming.
• Long-term mitigation strategies to reduce the urban heat island effect include planting street trees, installing green roofs, and using cool roofs and cool pavements.

APA

Hsu, A., Shandas, V., Manya, D., & Vecellio, D. J. (2023). Urban Heat Hot Spots. Climate Central. https://www.climatecentral.org/climate-matters/urban-heat-islands-2023

Chicago

Hsu, Angel, Vivek Shandas, Diego Manya, and Daniel J. Vecellio. Urban Heat Hot Spots. Climate Central, 2023. https://www.climatecentral.org/climate-matters/urban-heat-islands-2023.

Wikipedia

{{cite report |last1=Hsu |first1=Angel |last2=Shandas |first2=Vivek |last3=Manya |first3=Diego |last4=Vecellio |first4=Daniel J. |title=Urban Heat Hot Spots |publisher=Climate Central |date=26 July 2023 |url=https://www.climatecentral.org/climate-matters/urban-heat-islands-2023 |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{hsu2023urban, author = {Hsu, Angel and Shandas, Vivek and Manya, Diego and Vecellio, Daniel J.}, title = {{Urban Heat Hot Spots}}, institution = {Climate Central}, year = {2023}, month = jul, url = {https://www.climatecentral.org/climate-matters/urban-heat-islands-2023}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }