NIHHIS Monitor and Outook

The graphic above displays rates of heat-related illness (HRI) for a given week. Potential HRI is identified using syndromic surveillance data and methods. Syndromic surveillance uses near real-time data from chief complaints and diagnosis codes routinely collected during healthcare visits. The HRI syndrome is based on a well-defined combination of keywords and ICD codes that reflect potential adverse health episodes arising from exposure to high ambient temperature (see for more information on the syndrome). The rates shown for each HHS region reflect HRI-associated visits per 100,000 emergency room visits during the week using data available through the National Syndromic Surveillance Program at the Centers for Disease Control and Prevention.

The temperature data is obtained from the National Oceanic and Atmospheric Administration, and shows observed average maximum, minimum, and average temperatures in degrees Fahrenheit for the same one week period. Observations were not available outside of the continental United States from this data source.

The overlay of temperature and HRI data does not indicate a causal link. Instead, it provides information useful to public health agencies as they track variations in HRI along with temperature increases to plan for and communicate about HRI. Public health agencies that are interested in similar analyses on a state or local level should contact Shubhayu Saha, PhD:


Americans’ health, security and economic wellbeing are tied to climate and weather. Every day, we see communities grappling with environmental challenges due to unusual or extreme events related to climate and weather. In 2017, the United States experienced a record-tying 16 climate- and weather-related disasters where overall costs reached or exceeded $1 billion. Combined, these events claimed 362 lives, and had significant economic effects on the areas impacted, costing more than $306 billion. Businesses, policy leaders, resource managers and citizens are increasingly asking for information to help them address such challenges.


Climate Program Office
1315 East-West Hwy, Suite 1100
Silver Spring, MD 20910