Extreme Heat

Extreme heat is a period of high heat and humidity with temperatures above 90 degrees for at least two to three days. In extreme heat, your body must work harder to maintain a normal temperature, which can lead to death. Heat and heat waves are one of the leading weather-related killers in the United States, and results in hundreds of fatalities each year, but heat-related illnesses and death are largely preventable with proper planning, education, and action.

Hazards of a Heat

According to the National Weather Service (NWS) and the Centers for Disease Control (CDC), during extremely hot and humid weather, your body's ability to cool itself is challenged. When the body heats too rapidly, or when too much fluid or salt is lost through dehydration or sweating, body temperature rises and you may experience a heat-related illness. It is important to know the symptoms of excessive heat exposure and the appropriate responses.

Heat Cramps 

Heat cramps may be the first sign of heat-related illness, and may lead to heat exhaustion or stroke.


  • Heavy sweating during intense exercise
  • Muscle pain or spasms

First Aid: 

  • Stop physical activity and move to a cool place
  • Drink water or a sports drink
  • Wait for the cramps to go away before you do any more physical activity

Seek immediate medical attention if cramps last longer than an hour, you’re on a low-sodium diet, or you have heart problems.

Heat Exhaustion


  • Heavy sweating
  • Cold, pale, and clammy skin
  • Fast, weak pulse
  • Nausea or vomiting
  • Muscle cramps
  • Tiredness or weakness
  • Dizziness
  • Headache
  • Fainting (passing out)

First Aid: 

  • Move to a cool place
  • Loosen your clothes
  • Put cool, wet cloths on your body or take a cool bath
  • Sip water

Seek immediate medical attention if you vomit more than once, symptoms worsen or last longer than an hour.

Heat Stroke


  • High body temperature (103°F or higher)
  • Hot, red, dry, or damp skin
  • Fast, strong pulse
  • Headache
  • Dizziness
  • Nausea
  • Confusion
  • Losing consciousness (passing out)

First Aid: 

  • Call 911 right away, heat stroke is a medical emergency
  • Move the person to a cooler place
  • Help lower the person’s temperature with a cool cloth or a cool bath
  • Do not give the person anything to drink

Preparing for a Heat Wave

According to the NWS and CDC, Heat and heat waves are one of the leading weather-related killers in the United States, and result in hundreds of fatalities each year, but heat-related illnesses and death are largely preventable with proper planning, education, and action. 

Follow these tips on how to prepare for a heat wave and learn more from the provided additional resources:

  • Write or review your Family Emergency Plan: Before an emergency happens, sit down with your family or close friends and decide how you will get in contact with each other, where you will go, and what you will do in an emergency. Keep a copy of this plan in your emergency supplies kit or another safe place where you can access it in the event of a disaster. Make a plan at Ready.Gov
  • Prepare for your Family and Pets: Consider training in first aid to learn how to treat heat-related emergencies
  • Prep an emergency supply kit:   
    • Water: One gallon of water per person per day for several days, for drinking and sanitation  
    • Food: Have at least a several-day supply of non-perishable food such as canned food and a can opener, dry cereal, and protein-rich foods like nuts and energy bars
    • Baby, special needs gear: If you have a baby or family member with special needs, pack diapers, and any special formula or food
    • Pet supplies: Food and water   
    • Radio: Battery or hand cranked
    • Flashlight: Replace the batteries before the season starts and pack extras
    • First Aid Kit: Also check that you have essential medications
    • Basic toolkit: Pliers, wrench, screwdriver, or otherwise
    • Charged Cell Phone: Keep a spare charger as well  
  • Check air-conditioning ducts for proper insulation
  • Install window air conditioners snugly; insulate if necessary
  • Install temporary window reflectors: These are used between windows and drapes, such as aluminum foil-covered cardboard, to reflect heat back outside
  • Weather-strip doors and sills: This will help to keep cool air in
  • Cover windows that receive morning or afternoon sun: Use drapes, shades, awnings, or louvers. Outdoor awnings or louvers can reduce the heat that enters a home by up to 80 percent.
  • Sign Up for Notifications: The Advanced Hydrologic Prediction Service provides RSS feeds for observed forecasts to help keep the public informed about local water conditions

Staying Safe During a Heat Wave

Everyone can be vulnerable to heat, but some more so than others. Take precautions during extreme heat and heat waves:

  • Stay Hydrated: Hydrate with water throughout the day, even if you do not feel thirsty, and avoid sugary beverages or drinks with caffeine
  • Check on family, friends, and neighbors who do not have air conditioning and who spend much of their time alone
  • Check on animals frequently to ensure that they are not suffering from the heat. If they are outside, make sure they have plenty of cool water and access to comfortable shade. Asphalt and dark pavement can be very hot on your pet’s feet
  • Go to a designated public shelter if your home loses power during periods of extreme heat, or stay on the lowest floor out of the sunshine if air conditioning is not available
  • Stay Informed: Listen to radio and television, EAS, NOAA Weather Radio, or local alerting systems for current information and instructions regarding the heat wave

If you must be outside during a heat wave: 

  • Avoid strenuous work during the warmest part of the day. Use a buddy system when working in extreme heat, and take frequent breaks
  • Dress in loose-fitting, lightweight, and light-colored clothes that cover as much skin as possible. Avoid dark colors because they absorb the sun’s rays
  • Protect your face and head by wearing sunblock and a wide-brimmed hat
  • Postpone outdoor games and activities
  • Return indoors as much as possible and limit exposure to the sun

Be aware that people living in urban areas may be at greater risk from the effects of a prolonged heat wave than people living in rural areas.

Sources and Additional Resources

National Weather Service (NWS)
Center for Disease Control (CDC)