The Stay Cool Act authorizes $10 million annually from 2026 through 2035 for the Department of Housing and Urban Development to award grants to states, local governments, and tribes for public outreach campaigns about cooling centers and community resilience, including activities like creating websites and mobile apps to help residents locate these facilities during heat emergencies. The bill also establishes a separate $50 million annual grant program during the same period for constructing public water features such as splash parks, pools, and misting systems in communities with limited cooling access, with requirements that projects create employment opportunities for minorities and low-income residents. The legislation defines key terms including "cooling center" and "community resilience center," which are free, climate-controlled public facilities designed to serve as refuges during extreme heat, and specifies that eligible grant recipients include states, tribes, local governments, and nonprofits.