In an emergency, call 911 (US) or 999 (UK) and follow instructions from local officials first.

Disasters · US

Extreme heat

Stay cool without relying on a fan, and know the difference between heat exhaustion and heat stroke.

By The Ready TeamExpert review: pendingSources checked 29 October 2026

Quick card · Extreme heatSources checked 29 Oct 2026

Before

  • Find your nearest cooling center, library or mall. 1
  • Close blinds, weather-strip doors and windows, and add reflective window film or insulation. 1
  • Don't rely on a fan as your main way to cool down. 1

During

  • Never leave people or pets in a closed car on a warm day. 1
  • Drink fluids, take cool showers, wear loose light-colored clothing, and avoid hard work in midday heat. 1
  • Check on older relatives and neighbors. 1
  • Heat stroke (body temperature above 103°F, hot red dry skin, confusion): call 911, move the person somewhere cool, and put cold wet cloths on the head, neck, armpits and groin. 1
  • Heat exhaustion (heavy sweating, cramps, weakness, nausea): move somewhere cooler and sip water or a sports drink. Get medical help if it lasts more than an hour. 1

What to have

  • Reflective window film or reflectors 1
  • Weather-stripping 1
  • Window air conditioner, insulated around the edges 1

What counts as extreme heat

FEMA describes extreme heat as temperatures above 90 degrees for at least two to three days, often with high humidity. 1

Heat exhaustion or heat stroke?

Heat exhaustionHeat stroke
SignsHeavy sweating, paleness, cramps, tiredness, weakness, fast or weak pulse, dizziness, headache, nausea, faintingBody temperature above 103°F, red hot dry skin with no sweating, fast strong pulse, confusion or unconsciousness
What to doMove somewhere cooler, loosen clothing, sip water or a sports drink. Call a doctor if it gets worse or lasts over an hourCall 911. Move to shade, remove outer clothing, cool the head, neck, armpits and groin with cold wet cloths or ice packs

From FEMA’s Ready.gov. 1 Heat stroke is a medical emergency.

Help with cooling costs

If you can’t afford cooling or energy repairs, FEMA points to the Low Income Home Energy Assistance Program (LIHEAP). 1

Sources

  1. Ready.gov (FEMA), Extreme Heat