HeatWatch Charleston 2021

heat watch


The city of Charleston was selected to participate in HeatWatch, NOAA's National Integrated Heat Health Information System urban heat island mapping campaign.


 HeatWatch is a national effort to record the heat index throughout participating cities on a single day, to see how the heat index varies from one area of a city to the next. When one part of a city is much hotter than the surrounding areas, it is referred to as an Urban Heat Island. The data collected during the HeatWatch event on July 31, 2021, has been used to produce detailed maps of the cities’ urban heat islands. Using heat sensors mounted on their own cars or bikes, community volunteers traversed their neighborhoods morning, afternoon, and evening on one of the hottest days of the year. The sensors recorded temperature, humidity, time, and the volunteers’ location every second.

Why it matters

In 2020, the city of Charleston released an All Hazards Vulnerability and Risk Assessment report, which identified populations and assets throughout the city that are vulnerable to various physical threats. Among the threats identified in the report was extreme heat. 

While the report identifies extreme heat as a pressing public health risk--particularly for low-income and elderly communities living in developed areas with low tree canopy cover--more data is needed in order to understand urban heat and its impacts and the concerns of compound risks associated with extreme heat, humidity and flooding.

How will HeatWatch help?

The HeatWatch event will provide the city better data on urban heat islands and areas of concern, helping to focus efforts to reduce the risk of heat illness in the community to the areas that need it most. This data can then be integrated into city planning decisions and used to engage citizens on extreme heat risks and mitigation strategies in urban areas. By raising awareness of extreme heat risks and by layering data into the city’s GIS system, comprehensive, equitable and multi-benefit solutions will be possible.

What can you do?

One of the many benefits of a mature tree canopy is the mitigation effect it has on heat and flooding.  The following web apps explore Charleston tree canopy and helps to identify areas where new trees would be beneficial.

Additional Details

In Charleston, this effort is made possible due to the partnership between the city of Charleston; Medical University of South Carolina Arboretum, Institute for Air Quality Studies and Office of Health Promotion; Citadel James B. Near Center for Climate Studies; Charleston Resilience Network; Climate Adaptation Partners; Charleston Medical District; South Carolina Interfaith Power and Light; Carolinas Integrated Science Assessment.

Please email Dr. Janice Barnes (Project Manager for this project) at janice@climateadaptationpartners.com for any questions.

CAPA Heat Watch Statistics