Heat is one of the leading weather-related killers in the United States.

Each year, hundreds of people die due to heat-related illnesses and thousands become ill. Many of us can go inside and turn on the air conditioning, but for outdoor workers in very hot environments, it isn’t that simple. Outdoor workers are particularly vulnerable to heat stress. To encourage heat-related safety precautions, the National Weather Service teams up with the Occupational Safety and Health Administration every year to educate workers about excessive heat and ways to prevent heat illness.

NOAA’s Watch, Warning and Advisory products for extreme heat are based on a number of factors, including the heat index, which is calculated by combining the air temperature with humidity to determine how hot it feels. In direct sunlight, it is advised to add approximately 15 degrees to the heat index since it may feel even hotter in the sun. These products help employers and workers prepare for the heat by planning work schedules, acclimatizing, ensuring there is plenty of water and shade/air conditioning available, and time for breaks.

If you’re not sure how to calculate the heat index, or what the humidity is at a certain time, you can download the OSHA Heat Safety Tool. OSHA’s Heat Safety Tool is a smartphone application that calculates the heat index based on your current location, and provides a risk level and precautions to take. It was recently updated for iOS to be more…