Urban Heat Hot Spots in 65 Cities

Climate Central analyzed the urban heat island (UHI) index across 65 major U.S. cities, finding that 68% of the 50 million residents in these cities live in areas where the built environment increases temperatures by 8°F or more. The study identifies albedo, green space, and population density as the primary drivers of this effect. It also highlights a link between historical redlining and current heat disparities, noting that in 84% of 179 analyzed cities, historically redlined areas experience hotter summers than non-redlined areas.

• Across 65 major U.S. cities, approximately 33.8 million people—representing 68% of the 50 million residents analyzed—live in census block groups with an urban heat island (UHI) index of 8°F or higher.
• The per capita average UHI index varies by city, with New York City recording the highest at 9.7°F and Phoenix the lowest among the group at 7.4°F.
• Six cities have at least 1 million people exposed to a UHI index of 8°F or higher: New York, Los Angeles, Houston, Chicago, San Antonio, and Dallas.
• The three most significant factors influencing the UHI index are albedo (the reflection of solar radiation), the percentage of green space, and population density.
• Urban heat is strongly linked to historical racial discrimination in housing; in 150 of 179 U.S. cities (84%), historically redlined Grade D areas experienced summer temperatures 6.5°F hotter on average between 2013 and 2023 than Grade A areas.
• The highest disparities in summer heat due to redlining were found in Boston (14.3°F), Bergen County (13.8°F), Portland (13.3°F), and Oakland (12.6°F).
• Long-term mitigation strategies to reduce the urban heat island effect include planting street trees, installing green roofs, using cool roofs with high albedo materials, and implementing cool pavements.

APA

Krisch, M. (2024). Urban Heat Hot Spots in 65 Cities. Climate Central. https://www.climatecentral.org/climate-matters/urban-heat-islands-2024

Chicago

Krisch, Michael. Urban Heat Hot Spots in 65 Cities. Climate Central, 2024. https://www.climatecentral.org/climate-matters/urban-heat-islands-2024.

Wikipedia

{{cite report |last1=Krisch |first1=Michael |title=Urban Heat Hot Spots in 65 Cities |publisher=Climate Central |date=9 July 2024 |url=https://www.climatecentral.org/climate-matters/urban-heat-islands-2024 |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{krisch2024urban, author = {Krisch, Michael}, title = {{Urban Heat Hot Spots in 65 Cities}}, institution = {Climate Central}, year = {2024}, month = jul, url = {https://www.climatecentral.org/climate-matters/urban-heat-islands-2024}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }