North American summers are hot; most summers see heat waves in one or more parts of the United States. Heat is one of the leading weather-related killers in the United States, resulting in hundreds of fatalities each year and even more heat-related illnesses. In addition to the resources below, OSHA offer free OSHA Heat Safety App for both Android and iPhone.

This website is designed to inform you about the health dangers of heat, prepare you for excessive heat events, and tell you what to do during an excessive heat wave. This site includes vital information about the dangers of leaving children, pets or anyone with limited mobility alone in a car even for a few minutes in what might seem like mild weather. Here you will find information about protecting yourself from the heat, educational materials and resources on how the National Weather Service keeps you aware of potentially dangerous situations. You will also find games and activities to help educate your children about the dangers of heat and links for more information.

Read about real life heat victims. You can also see our heat safety videos. If you, or someone you know, have been a victim of excessive heat, please share your story so we can prevent others from becoming a heat victim. When you write, please note that NWS has permission to use your story and, if possible, let us know the town and state you were in and the year the event took place.

The Heat Index is a measure of how hot it really feels when relative humidity is factored in with the actual air temperature. To find the Heat Index temperature, look at the Heat Index Chart above or check our Heat Index Calculator. As an example, if the air temperature is 96°F and the relative humidity is 65%, the heat index--how hot it feels--is 121°F. The red area without numbers indicates extreme danger. The National Weather Service will initiate alert procedures when the Heat Index is expected to exceed 105°-110°F (depending on local climate) for at least 2 consecutive days.

NWS also offers a Heat Index chart for area with high heat but low relative humidity. Since heat index values were devised for shady, light wind conditions, exposure to full sunshine can increase heat index values by up to 15°F. Also, strong winds, particularly with very hot, dry air, can be extremely hazardous.