Heat related illnesses are the leading cause of mortality among weather related natural disasters in the United States. With the growing concern over global climate change and urbanization related regional climate change, outcomes of heat related illnesses can become worse without preparation. People who are homeless have increased vulnerabilities that predispose them to poor outcomes from heat related illnesses. Other than lack of shelter, these vulnerabilities can include poor access to healthcare and vital resources, compromised mental health, as well as lack of knowledge about heat related illnesses. While homeless veterans have access to services through the Department of Veterans Affairs, access can be hindered by unreliable transportation, trust, and the acute need of care. The study included 644 surveys from the homeless population in the Tampa Bay Area. While veterans were found to have less concern about health during hot weather (52% veterans to 57% non-veterans reporting health concern during hot weather) and better access to water (90.5% veterans to 86% non-veterans reporting access to water), neither difference is statistically significant. When surveyed about warning symptoms of heat related illness, only dizziness was recognized by more than 50% of subjects (56.10%). To improve outcomes from heat related illnesses, a multi-faceted approach is needed. Cities should create plans for heat waves, provide water/shelters, educate susceptible populations, and optimize medical care. Clean water should be made accessible to all of the homeless population through bottle water or water purification devices. In addition to municipal planning, veteran services organizations should target the needs of veterans by mobile medical care and shelters which can be used during heat events. (C) 2016 Elsevier Ltd. All rights reserved.