Extreme Weather and Heat Response Modernization Act This bill requires the Federal Emergency Management Agency (FEMA) to specifically address extreme heat in hazard mitigation and disaster recovery, including reviewing the time frame for when extreme weather is an emergency or major disaster. FEMA must issue guidance relating to hazard mitigation and disaster recovery for extreme heat or extreme temperature events. FEMA must also convene an advisory panel to review its process for determining when an emergency- or disaster-causing incident begins and ends. Additionally, FEMA must conduct a study on the impacts of extreme heat, recommend guidance on mitigating and responding to extreme heat, and submit a report to Congress on these actions. The bill also authorizes FEMA to consider extreme heat preparedness and mitigation projects eligible under its Building Resilient Infrastructure and Communities program and Hazard Mitigation Grant Program.