Federal Agencies, Communities to Map Heat Inequities In 14 U.S. Cities

Identifying these areas, called urban heat islands, helps communities take action to reduce the health impacts of extreme heat and provides cooling relief for those living in the hottest areas. 

Now in its eighth year, the NOAA Urban Heat Island mapping campaign addresses extreme heat, the number one weather-related cause of death in the U.S. for the last three decades. Summer 2023 was Earth’s hottest on record, and communities across the globe felt this heat, impacting health, infrastructure, agriculture and more. 

Urban heat islands, areas with few trees and more pavement that absorbs heat, can be up to 20 degrees Fahrenheit hotter than nearby neighborhoods. To map these areas and collect the data necessary to protect disproportionately affected communities, the NOAA Climate Program Office (CPO), the interagency National Integrated Heat Health Information System (NIHHIS), HHS, HUD and CAPA Strategies, LLCoffsite link will work with each of the participating communities.

Communities chosen for the 2024 program are: Bloomington, Indiana; Calexico, California; Charlotte, North Carolina; Flint, Michigan; Fort Wayne, Indiana; Grand Junction, Colorado; Hennepin and Ramsey Counties, Minnesota; Laredo, Texas; Pierce County, Washington; Reno and Sparks, Nevada; Santa Fe, New Mexico; and Unincorporated Norcross, Georgia. The international campaigns will take place in Mexicali, Mexico; Dhaka, Bangladesh; Nairobi, Kenya; and Salvador, Brazil. International campaigns were previously completed in Freetown, Sierra Leone, Rio de Janeiro, Brazil, and Santiago, Chile.  

Local campaigns in the U.S. and abroad do not receive direct funding from NOAA. Instead, over the past seven years, NOAA has funded CAPA Strategies, a U.S. company, to provide science support, including sensors, planning assistance and map creation based on data collected by community volunteers. CAPA Strategies has supported more than 70 community-led urban heat island mapping campaigns in the U.S. and international communities by recruiting volunteers to conduct heat data. Communities also bring their own financial and in-kind support from partners that include nonprofit organizations, city government agencies, schools, science museums and international foundations. 

While the emphasis of the program is on urban heat island mapping in U.S. cities, a smaller number of international campaigns benefit U.S. communities because they broaden the scope of lessons that can be learned from how other countries tackle extreme heat. They also enable the U.S. to share best practices more broadly.

Using heat sensors mounted on their own cars, volunteer community scientists, led by a team of local partners in each city, traverse their neighborhoods in the morning, afternoon and evening on one of the hottest days of the year. The sensors record temperature, humidity, time and the volunteers’ location every second. CAPA's end-to-end program, including sensor technology, community engagement, analysis and modeling allows communities to develop hyper-local descriptions of where the hottest parts of their community are and strategize mitigation options specific to each region of the country. 

The cities and counties selected this year have a range of experiences with extreme heat, but each is looking for equitable ways to implement cooling solutions in their communities. For example, Pierce County, Washington, was one of the many counties in the Pacific Northwest that faced an unprecedented heat wave in June 2021. Hundreds of lives were lost in the region, including 159 deaths in Washingtonoffsite link and 29 deaths in Pierce County. Throughout the state, high temperatures buckled roadways, melted train power lines and damaged other infrastructure, while also scorching forests that were not adapted to the extreme conditions. 

During the 2023 urban heat island campaigns, 942 community scientists took more than one million measurements in 19 U.S. communities. The data and maps from the campaigns are open access and available on HEAT.gov. 

Previous and current communities participating in the UHI campaigns are part of a community of practice where they are able to share best practices and network with other cities addressing extreme heat. Many of the communities have implemented cooling solutions based on the heat maps, including securing federal funding for tree planting initiatives, establishing cooling centers, developing heat action plans, educating the public on heat and more. 

When evaluating applications for the 2024 heat island mapping campaigns, the NIHHIS team gave significant weight to applications emphasizing their commitment to addressing environmental justice.