The main purpose of the Extreme Weather and Heat Response Modernization Act is to improve how the Federal Emergency Management Agency (FEMA) manages responses to extreme weather events, particularly those related to heat and cold. The legislation aims to enhance preparedness, mitigation, and response strategies for various disasters, ensuring that communities are better equipped to handle these challenges. Key provisions of the Act include the establishment of an advisory panel to review and improve the process for determining incident periods for emergencies and disasters.