What is the difference between heat exhaustion and heat stroke?

Heat exhaustion causes heavy sweating, weakness, cold and clammy skin, nausea, and dizziness. Move the person to a cool place, apply cool cloths, and have them sip water. Heat stroke is a life-threatening emergency: the body temperature rises above 103 degrees F, the skin is hot and dry (no sweating), and the person may be confused or unconscious. Call 911 immediately. The CDC classifies heat stroke as a medical emergency requiring immediate treatment.

How much water should I drink during a heat wave?

The CDC recommends drinking water throughout the day, even if you do not feel thirsty. For most adults, this means at least 8 to 12 glasses per day during extreme heat, and more if you are working or exercising outdoors. Avoid alcohol and heavily caffeinated beverages, which can contribute to dehydration.

Who is most at risk during extreme heat?

Adults over 65, infants and young children, people with chronic medical conditions (heart disease, diabetes, respiratory conditions), people who work outdoors, people without air conditioning, and people taking certain medications (diuretics, beta-blockers, antipsychotics) are most vulnerable. The CDC considers people over 65 the highest-risk group for heat-related illness.

What should I do if my air conditioning fails during a heat wave?

Go to a public cooling center, library, mall, or a friend or family member's home with working AC. If you must stay home, move to the lowest floor, close curtains, use fans to circulate air, take cool showers, and apply wet cloths to pulse points (wrists, neck, ankles). Do not rely on fans alone when temperatures exceed 95 degrees F, as they can accelerate dehydration without cooling the body.

Can I leave children or pets in a parked car during hot weather?

Never. A car's interior temperature can rise 20 degrees in just 10 minutes, even with windows cracked. On a 90 degree day, the interior can reach 119 degrees in 20 minutes. Children and pets die in hot cars every year. The NHTSA reports an average of 38 child hot car deaths annually in the United States.

Extreme Heat Preparedness Checklist — Before, During & After a Heat Wave

Phase 1

Before the heat arrives. Prepare your home. Know the signs.

Extreme heat kills more Americans than any other weather hazard. Most heat deaths are preventable with preparation and awareness.

Home Cooling

Service your air conditioning before the season (clean filters, check refrigerant, test operation)
Install window coverings, blackout curtains, or reflective film on south- and west-facing windows
Identify the coolest room in your home in case the AC fails
Locate your nearest public cooling center, library, or mall with AC

Supplies

Stock extra drinking water (at least 1 gallon per person per day)
Keep electrolyte drinks or oral rehydration salts on hand
Sunscreen (SPF 30+), wide-brimmed hats, and lightweight light-colored clothing
Battery-powered fan as backup if power fails

Know the Warning Signs

Heat exhaustion: heavy sweating, weakness, cold/clammy skin, nausea, dizziness. Move to cool place, sip water
Heat stroke: body temp above 103 degrees F, hot/dry skin, confusion, loss of consciousness. Call 911 immediately
Review medications with your doctor: some increase heat sensitivity (diuretics, beta-blockers, antipsychotics)
Make a plan to check on elderly neighbors, people who live alone, and anyone without AC

Pets and Children

Never leave children or pets in a parked car, not even for a minute, not even with windows cracked
Test pavement with the back of your hand before walking dogs (if it is too hot for your hand, it is too hot for paws)
Ensure pets have shade and fresh water at all times
Schedule outdoor activities for early morning or evening when temperatures are lower

Phase 2

During extreme heat. Drink before you are thirsty.

By the time you feel thirsty, you are already dehydrating. During a heat wave, drink water continuously, limit outdoor exposure, and watch for signs of heat illness in yourself and others.

Hydration and Activity

Drink water throughout the day, even if you do not feel thirsty
Avoid alcohol and heavily caffeinated beverages (they contribute to dehydration)
Limit outdoor activity to early morning or evening. Avoid strenuous work during peak heat (10 AM to 4 PM)
If you must work outdoors, take a break in shade every 15 to 20 minutes and drink water

Cooling Strategies

Close curtains and blinds on sun-facing windows during the day
Take cool showers or apply wet cloths to pulse points (wrists, neck, ankles)
Do not rely on fans alone above 95 degrees F (they move air but do not cool the body, and can accelerate dehydration)
If your AC fails, go to a public cooling center. Do not wait until you feel sick

Phase 3

After the heat breaks. Keep hydrating. Check on others.

Your body needs time to recover even after temperatures drop. Continue drinking water and avoid heavy exertion for 24 to 48 hours.

Continue drinking water and eating light meals for 24 to 48 hours after extreme heat
Check on elderly neighbors, people who live alone, and anyone who was without AC
Inspect outdoor plants, gardens, and landscaping for heat damage and water deeply
Restock water supplies, electrolyte drinks, and sunscreen for the next heat event
If your AC struggled, schedule a service call before the next heat wave

Gear

Heat essentials. Start here.

A few items help you keep your household cool and hydrated when temperatures become dangerous.

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Extreme Heat Preparedness Checklist. Stay cool. Stay hydrated. Stay alive.