This SAMHSA guide explores the link between extreme heat and mental health, highlighting how rising temperatures can increase anxiety, depression, and emotional distress, especially among individuals with existing mental health or substance use conditions. The report outlines populations most at risk—such as the elderly, people with chronic illnesses, and those living without access to cooling. It offers strategies for communities, caregivers, and behavioral health professionals to prepare for and respond to mental health needs during extreme heat events. This resource supports public health planning to address the growing intersection between climate change and mental well-being.