Heat-Related Illness

Heat surveillance seasons for each year are defined based on when summer heat begins and ends and may vary from year-to-year.

Learn more about heat-related illnesses and how to prevent them:

Data Definitions

Heat-related illness (HRI): Emergency department visits among Tarrant County residents possibly related to illness caused by environmental heat exposure.
Heat-related death: Deaths among Tarrant County residents in which the cause of death is determined to be hyperthermia (overheating). Data subject to change due to on-going investigations.
Ozone Action Day: Day in which the eight-hour average measurement for ozone level reaches or exceeds EPA’s Air Quality Index (AQI) Level Orange (“Unhealthy for Sensitive Groups”).
Minimum Temperature (Min Temp): Lowest measured temperature for the day (Fahrenheit), based on measurement from the DFW International Airport weather station.
Maximum Temperature (Max Temp): Highest measured temperature for the day (Fahrenheit), based on measurement from the DFW International Airport weather station.

Data Definitions for Heat-Related Injuries Type

Heat Stroke: ICD-10 diagnosis code for heat stroke or sun stroke.
Heat Exhaustion: ICD-10 diagnosis code for heat exhaustion.
Heat Cramps: Mention of ‘heat cramp’ or ICD-10 diagnosis code for heat cramp.
Sunburn: Mention of ‘sunburn’ or ICD-10 diagnosis code for sunburn.
Other Heat-Related Illness: All remaining visits for HRI, such as: heat exposure, rash, sickness/illness, stress, and syncope; overheating; and other HRIs not included in prior categories.