This bill, titled the "Preventing HEAT Illness and Deaths Act of 2025," seeks to significantly reduce health risks associated with extreme heat across the United States. It achieves this by establishing two key federal entities: the National Integrated Heat Health Information System (NIHHIS) within the National Oceanic and Atmospheric Administration (NOAA) and the National Integrated Heat Health Information System Interagency Committee . The Interagency Committee is tasked with coordinating a unified federal approach to addressing heat-related health risks over various timescales. Its broad membership includes representatives from numerous federal departments and agencies, such as Commerce, Health and Human Services, EPA, and Homeland Security, ensuring a comprehensive, interdisciplinary effort. The Committee will develop a 5-year strategic plan to improve coordination, data management, research, and financing mechanisms for heat planning and response. The NIHHIS, headed by a Director, aims to improve the delivery of heat-related data, forecasts, and warnings, particularly for disproportionately affected communities. It will develop and maintain science-based solutions and tools to enhance heat resilience and provide grants to centers of excellence. The Director will foster robust relationships with federal and non-federal partners, including emergency management, health professionals, and community representatives, to identify needs and deliver actionable information. Key responsibilities of the NIHHIS Director also include coordinating with the international community, enhancing observations and monitoring, and building public awareness regarding heat risks. The system emphasizes open data availability, adhering to FAIR and CARE principles, and establishing a climate and health research grant program. This program will improve understanding of heat-health vulnerability, drivers of extreme heat, and the effectiveness of risk management actions. The bill mandates a comprehensive study by the National Academies of Sciences, Engineering, and Medicine on extreme heat information and response. This study will identify policy and research gaps, including regions with the largest disparities in heat awareness and capacity, and data gaps related to affected demographics and infrastructure. It will also provide recommendations for addressing these gaps in planning, preparedness, response, and resilience, with a focus on environmental justice and equity. Furthermore, the legislation establishes a Community Heat Resilience Program to provide financial assistance to eligible entities. This program supports projects designed to reduce heat-health risks through sustainable solutions like cool roofs, urban forestry, and cooling centers. It also funds training programs, capacity building, and public awareness campaigns to help communities respond to extreme heat events and establish local action plans. In selecting projects for financial assistance, the Director must prioritize entities benefiting historically disadvantaged communities and those with significant heat disparities. Not less than 40 percent of the financial assistance must be directed to projects in communities with environmental justice concerns or low-income communities, ensuring equitable distribution. The bill authorizes significant appropriations for these initiatives, including $20 million annually for the NIHHIS and Interagency Committee, $500,000 annually for the study, and increasing amounts for financial assistance, reaching $30 million by fiscal year 2029.