Methodology and Additional Source Info: This data was measured by the National Aeronautics and Space Administration (NASA)'s Landsat 8 satellite's earth observations, measured from 2013-2020 during the summer months (June, July, and August). The data was compiled and mapped for Fairfax County through a partnership between the Fairfax County Office of Environmental and Energy Coordination (OEEC) and the NASA DEVELOP program as part of the "Resilient Fairfax" Climate Adaptation and Resilience Plan process.Description: All areas of Fairfax County are exposed to extreme heat, and as temperatures continue to rise, this heat exposure is increasing. However, certain areas of the county experience significantly hotter on-the-ground temperatures than other areas. This map layer shows the average surface (on the ground) temperatures for Fairfax County, VA, measured from 2013-2020 during the summer months (June, July and August). The areas shown in light yellow-orange are cooler areas, while the areas shown in dark red are the hottest areas in Fairfax County. The highest surface temperature recorded was 126 degrees.The dark red areas on this map layer are known as "urban heat islands." The "urban heat island effect" happens because surfaces like parking lots, roads, dense buildings, and other infrastructure absorb and retain heat. In contrast, areas with ample green space, trees, and light-colored surfaces such as white roofs are much cooler. Because of the "urban heat island effect," real temperatures within these hot spots on any given day are often much hotter than the general weather forecast for that day. For example, if the general temperature in Fairfax County for a particular day is 80 degrees F, the real temperature in the "urban heat islands" may be 100 degrees F. As overall temperatures rise, temperatures will continue to be even higher within the urban heat islands. The purpose of this map is to enable Fairfax County residents, staff, and stakeholders, to see the locations of urban heat islands in Fairfax County. When we know the locations of these urban heat islands, we are able to make better plans to address extreme heat.

Methodology and Additional Source Info: This data was measured by the National Aeronautics and Space Administration (NASA)'s Landsat 8 satellite's earth observations, measured from 2013-2020 during the summer months (June, July, and August). The data was compiled and mapped for Fairfax County through a partnership between the Fairfax County Office of Environmental and Energy Coordination (OEEC) and the NASA DEVELOP program as part of the "Resilient Fairfax" Climate Adaptation and Resilience Plan process.Description: All areas of Fairfax County are exposed to extreme heat, and as temperatures continue to rise, this heat exposure is increasing. However, certain areas of the county experience significantly hotter on-the-ground temperatures than other areas. This map layer shows the average surface (on the ground) temperatures for Fairfax County, VA, measured from 2013-2020 during the summer months (June, July and August). The areas shown in light yellow-orange are cooler areas, while the areas shown in dark red are the hottest areas in Fairfax County. The highest surface temperature recorded was 126 degrees.The dark red areas on this map layer are known as "urban heat islands." The "urban heat island effect" happens because surfaces like parking lots, roads, dense buildings, and other infrastructure absorb and retain heat. In contrast, areas with ample green space, trees, and light-colored surfaces such as white roofs are much cooler. Because of the "urban heat island effect," real temperatures within these hot spots on any given day are often much hotter than the general weather forecast for that day. For example, if the general temperature in Fairfax County for a particular day is 80 degrees F, the real temperature in the "urban heat islands" may be 100 degrees F. As overall temperatures rise, temperatures will continue to be even higher within the urban heat islands. The purpose of this map is to enable Fairfax County residents, staff, and stakeholders, to see the locations of urban heat islands in Fairfax County. When we know the locations of these urban heat islands, we are able to make better plans to address extreme heat.