The NWS HeatRisk is an experimental color-numeric-based index that provides a forecast risk of heat-related impacts to occur over a 24-hour period. HeatRisk takes into consideration:

• How unusual the heat is for the time of the year
• The duration of the heat including both daytime and nighttime temperatures
• If those temperatures pose an elevated risk of heat-related impacts based on data from the CDC

This index is supplementary to official NWS heat products and is meant to provide risk guidance for those decision makers and heat-sensitive populations  who need to take actions at levels that may be below current NWS heat product levels.