Extreme Heat

Overview

Heat causes more deaths in the United States each year than floods, storms, and lightning combined. Since 1979, more than 14,000 Americans have died directly from heat-related causes, and 2023 set a record for U.S. heat deaths. Throughout Los Angeles County, we're already seeing the impacts of climate change, including hotter, longer heat waves that are one of the major threats to the health and wellbeing of our communities.

Excessive heat is defined as a long period of high temperatures and conditions that result in an increased risk to health and safety, especially for populations who are particularly vulnerable.

Sources: EPA Climate Change Indicators; Los Angeles County Public Health

Know Your Heat Risk Level

Visit the National Weather Service (NWS) HeatRisk website to see current heat risk levels for our area. The system shows color-coded risk levels from green (little risk) to red (dangerous heat).

 

Before Extreme Heat

Prepare Your Home

  • Service your air conditioning - Have it inspected and ensure proper insulation around units
  • Seal air leaks - Weather-strip doors and windows to keep cool air inside
  • Block the sun - Install window coverings, shades, or awnings on windows that get direct sunlight
  • Check your cooling plan - Know where you'll go if your AC fails (cooling centers, friends/family with AC)

Prepare Yourself and Family

  • Build an emergency kit and make a family communications plan
  • Know vulnerable neighbors who may need help: elderly, young children, those with chronic conditions, pregnant women, and people living alone
  • Get trained in first aid to recognize and treat heat-related emergencies
  • Stay aware of weather forecasts and upcoming temperature changes

 

During Extreme Heat

Essential Safety Actions

  • Stay indoors during peak heat hours (11 AM - 4 PM)
  • Never leave children or pets in vehicles - Cars can reach deadly temperatures in minutes. Call 911 if you see a child or pet alone in a car
  • Drink water regularly - Even before you feel thirsty. Avoid alcohol and caffeine
  • Dress for heat - Lightweight, light-colored, loose-fitting clothes and wide-brimmed hats
  • Use sunscreen - SPF 30 or higher when going outside
  • Check on others - Especially elderly neighbors, those with medical conditions, and people living alone

If You Don't Have Air Conditioning

  • Go to cool spaces - Libraries, malls, cooling centers, community centers
  • Call 211 to find cooling locations near you
  • Take cool showers or baths
  • Use fans effectively - They can make rooms feel 3-4 degrees cooler
  • Avoid heat sources - Don't use ovens or stoves during the day
  • Stay on lower floors away from direct sunlight

Reduce Energy Use (Help Prevent Power Outages)

  • Set air conditioner (AC) to 78°F or higher
  • Use fans with AC to feel cooler at higher temperatures
  • Run major appliances early morning or late at night
  • Unplug devices when not in use

Recognize Heat-Related Illness

Call 911 Immediately if someone has:

  • High body temperature (103°F or higher)
  • Hot, red, dry, or damp skin
  • Fast, strong pulse
  • Dizziness or confusion
  • Nausea or vomiting
  • Headache
  • Passing out

Who's Most at Risk

  • Adults 65 and older
  • Children under 4
  • Pregnant women
  • People with chronic medical conditions
  • Outdoor workers and athletes
  • People taking certain medications
  • Those living alone

Check on vulnerable family, friends, and neighbors regularly.

Special Considerations

Children

  • Never leave children in parked vehicles
  • Reduce or reschedule outdoor activities to early morning (4-7 AM)
  • Ensure children drink water regularly, even before they ask
  • Provide plenty of rest - heat makes children tired
  • Find air-conditioned spaces if your home lacks cooling

Seniors

  • May not sense temperature changes as well as younger people
  • Medications can affect the body's ability to regulate temperature
  • Check on senior neighbors and relatives frequently

Pets

  • Never leave pets in parked vehicles
  • Walk pets on grass, not hot asphalt that can burn paws
  • Provide plenty of water and shade
  • Limit exercise during hot weather
  • Don't rely on fans - they don't cool pets effectively
  • Light-colored and hairless pets can get sunburn

 

Understanding Heat Alerts

Heat Advisory

Issued when dangerous heat conditions are forecast that may cause heat-related illness. In Los Angeles County, this is typically when daytime temperatures are expected to reach the mid-90s to low 100s°F, though exact thresholds vary by specific region.

Extreme Heat Warning (formerly Excessive Heat Warning)

Issued 12-24 hours before extremely dangerous heat conditions begin. In Los Angeles County, this is generally when temperatures are expected to reach 100-110°F or higher for extended periods, though criteria vary by location within the county.

Heat Index

How hot it feels when humidity is combined with the actual air temperature. Direct sunlight can increase the heat index by up to 15 degrees.

HeatRisk

The National Weather Service's color-coded forecast that shows heat risk levels from green (little to no risk) to magenta (rare and dangerous heat). This is now the primary tool for assessing heat danger in your specific area.

 

Emergency Resources

Immediate Help

  • Call 911 for medical emergencies
  • Call 211 for cooling center locations and emergency information (available 24/7)

Find Cooling Centers

Current Information

Additional Resources

Stay informed, stay hydrated, and check on others. Heat-related illness is preventable.