• Extreme heat is the leading cause of weather-related deaths in the United States.
• In the future, Harris County is expected to have higher temperatures and more extreme heat days.
• High temperatures and humidity can cause heat-related illnesses, such as heat cramps, heat exhaustion and heat stroke.
• Certain populations, such as the elderly, young children, and those with diabetes, are at  increased risk of heat-related illnesses.
• Reducing exposure to high outdoor temperatures and having access to air conditioning can provide relief and prevent heat-related illnesses.
• There are ways to reduce urban heat through better urban design, the addition of trees and greenspace, and the reduction of greenhouse gas emissions.

Hot and humid weather is typical within Harris County and Southeast Texas. According to the Climate Impact Assessment for the City of Houston, more extreme heat days, hotter nights, longer summers and higher energy demands are projected for the Greater Houston Area in the future.

When temperatures become extremely high and humidity levels peak, heat stroke, heat exhaustion, heat cramps and dehydration become a concern. Extreme heat can also exacerbate pre-existing conditions such as cardiovascular disease, asthma, chronic obstructive pulmonary disease (COPD), and diabetes.

The Extreme Heat Vulnerability Assessment is the first of several climate vulnerability assessments the Climate Program has planned. Areas with the most exposure, the highest population sensitivity, and the least ability to adapt will be identified as the highest priority for public health interventions. Flooding and Air Quality Vulnerability Assessments are planned for 2021.

This assessment combines health, economic, governmental, community, and environmental indicators together to create a vulnerability score for each census tract. The vulnerability score allows us to compare different areas to one another. The score assigned to each census tract is calculated using sixteen different indicators. The indicators are separated into three different categories: exposure, sensitivity, and adaptive capacity. A combination of these categories calculates the overall vulnerability score. For more in-depth explanation of the vulnerability assessment and calculations, please see the Methods document.

* Heat Index: According to the National Weather Service, the heat index is what the temperature feels like to the human body when relative humidity is combined with the air temperature.

The map below depicts the overall vulnerability for extreme heat and health throughout Harris County. Click on the map for an interactive look at all of the indicators. Click here to open this map in a new tab.