Prepare for Extreme Heat

July 26, 2022

Extreme Heat often results in the highest number of annual deaths among all weather-related hazards. In most of the United States, extreme heat is defined as a long period (2 to 3 days) of high heat and humidity with temperatures above 90 degrees. In extreme heat, evaporation is slowed and the body must work extra hard to maintain a normal temperature. This can lead to death by overworking the human body. Remember that:

  • Extreme heat can occur quickly and without warning.
  • Older adults, children, and sick or overweight individuals are at greater risk from extreme heat.
  • Humidity increases the feeling of heat as measured by a heat index.
A woman and a man sitting on a porch stoop due to extreme Heat

Heat kills by pushing the human body beyond its limits. In extreme heat and high humidity (which is when the air has moisture and feels sticky) the body must work extra hard to maintain a normal temperature and keep the body comfortable. A heat wave is an extended period of extreme heat, and there is often high humidity. These conditions can be dangerous for people who don’t take care of themselves properly.

Visit the FEMA library to download more facts about Extreme Heat


  • Build an emergency kit.
  • Make a family communications plan.
  • Keep shades closed on windows that get morning or afternoon sun.


  • Never sit in a parked car.
  • Stay inside as much as possible.
  • Play indoor games and sports.
  • Drink lots of water. This is your body’s air conditioning!
  • Wear loose-fitting clothes in light colors. Did you know dark colors absorb the sun’s rays?
  • Wear a hat with a wide brim to protect your face and head.
  • Spend time in places with air conditioning, like the library or movie theater.


Am I at Risk?

Sickness can occur if someone has been in extreme heat for too long, or has over-exercised for his or her age or physical condition. Extreme heat can be more dangerous for older people, the very young, and people who are sick or overweight. People who live in cities can be at greater risk because concrete and asphalt store heat for longer and release it throughout the night, so nights don’t get as cool as in areas with less concrete.

Words to Know!


The amount of water vapor in the air. Humidity is invisible and can make sweating less effective.


The measure of how hot or cold something is

Heat Stroke

When the body temperature gets too high and can make someone breathe fast, feel dizzy, throw up, get headaches, or feel weak. This can be deadly.


A dangerous condition where the body absorbs more heat than it can get rid of.

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