Climate & Health - High Heat Index Days

This indicator reports the percentage of recorded weather observations with heat index values over 103 degrees Fahrenheit. The "heat index" is a single value that takes both temperature and humidity into account. The higher the heat index, the hotter the weather feels, since sweat does not readily evaporate and cool the skin. The heat index is a better measure than air temperature alone for estimating the risk to workers from environmental heat sources.
Report Area Total Weather Observations Average Heat Index Value Observations with High Heat Index Values Observations with High Heat Index Values, Percentage
Franklin County, PA 4,380 90.28 48 1.1%
Pennsylvania 288,715 89.7 2,339 0.8%
United States 19,094,610 91.28 897,155 4.7%
Note: This Indicator is compared with the state average. Green - Better than state average, Red - Worse than state average.
Data Source: National Oceanic and Atmospheric Administration, North America Land Data Assimilation System (NLDAS) .
Accessed via CDC WONDER . Additional data analysis by CARES. 2014. Source geography: County
Website Updated August 2016

Climate & Health - High Heat Index Days

Data Background

NLDAS Phase 2 is a collaboration project among several groups, including the National Oceanic and Atmospheric Administration (NOAA), the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC), Princeton University, the National Weather Service (NWS), the University of Washington, and the NCEP Climate Prediction Center (CPC). The NLDAS data available on CDC WONDER are county-level daily average air temperatures and heat index measures spanning the years 1979-2011. Temperature data are available in Fahrenheit or Celsius. Reported measures are the average temperature, number of observations, and range for the daily maximum and minimum air temperatures, and the daily maximum heat index. For more information, please see the complete NLDAS Dataset Documentation .


Heat Index data are available for days with temperatures at or above 80 degrees Fahrenheit ( 26.7 degrees Celsius). Indicator maps and data report the number of percentage of total weather observations in 2014 where heat index values exceed 103°F, which constitutes a "High" risk level according to OSHA guidelines . The US Department of Labor and The U.S. National Oceanographic and Atmospheric Administration (NOAA) developed the heat index system, which combines both air temperature and relative humidity into a single value that indicates the apparent temperature in degrees Fahrenheit. The higher the heat index, the hotter the weather will feel, and the greater the risk that those outdoors will experience heat-related illness. NOAA issues heat advisories as the heat index rises. To learn more about the heat index, visit NOAA’s website .


Race and Ethnicity
Race and ethnicity (Hispanic origin) are collected as two separate categories in the American Community Survey (ACS) based on methods established by the U.S. Office of Management and Budget (OMB) in 1997. Indicator race and ethnicity statistics are generated from self-identified survey responses. Using the OMB standard, the available race categories in the ACS are: White, Black, American Indian/Alaskan Native, Asian, and Other. An ACS survey respondent may identify as one race alone, or may choose multiple races. Respondents selecting multiple categories are racially identified as “Two or More Races”. The minimum ethnicity categories are: Hispanic or Latino, and Not Hispanic or Latino. Respondents may only choose one ethnicity. All social and economic data are reported in the ACS public use files by race alone, ethnicity alone, and for the white non-Hispanic population.

Courtesy: Community Commons, <>, August 2016