To reduce the risk of heat illness that arrives with hot days, the National Integrated Heat Health Information System (NIHHIS) encourages municipalities to gather data and produce a map of their community’s hottest neighborhoods. Pending availability of federal funds, NIHHIS intends to provide financial support to 20 cities where groups are willing to organize and run volunteer mapping campaigns, and then engage municipal leaders in addressing their issues of urban heat. The application for funding is now available.