Safety & emergency preparedness

Excessive heat

Excessive heat is when temperatures are 10 degrees Fahrenheit more than the normal temperature. This can cause health problems, especially for seniors, pregnant women, infants, and children. Hot temperatures can also result in utility disruptions and bad weather such as thunderstorms, hurricanes, and tropical storms.

Differences between a warning and a watch

The following terms are frequently used on television and radio news broadcasting stations, during times when the City is experiencing excessive heat warnings and watches:

Excessive heat outlook            

A warning that extremely hot weather might occur within the next three-seven days. This warning is given to help public health officials, emergency managers, and public utilities prepare for a possible excessive heat event.

Excessive heat watch

A warning that an excessive heat event might occur in the next 12-48 hours. This warning is used when there is a high risk of an excessive heat event, but officials cannot yet determine the exact time frame of the event.

Excessive heat warning/advisory       

Warnings that are both used when an excessive heat event is expected in the next 36 hours.  An “excessive heat warning” is used when conditions could harm life or property. “Excessive heat advisory” is a less serious warning, when conditions are severe enough to cause physical discomfort and lead to more severe conditions that could harm life or property.

Excessive heat related terms

  • Heat index– the heat index (HI), or the “apparent temperature,” measures how the combination of high heat and humidity affects the human body. The HI is an indication of what the air temperature feels like when humidity is included.
  • Heat wave– the National Weather Service defines a heat wave as a temperature of 90 degrees Fahrenheit or higher for at least three days.
  • Ozone advisory– a warning used when the ground level ozone (a pollutant) is high. When this advisory is issued, outdoor activities should be limited and those with breathing problems, such as asthma, should refrain from heavy physical activity.

Stay safe

Code Orange – defined by the Environmental Protection Agency is a time where the Air Quality Index is at an unhealthy level for sensitive groups. This means that people within sensitive groups may experience health effects, yet the general public is not likely to be affected.

Code Red – defined as when the National Weather Service extended weather forecast includes at least three consecutive days of 95 degrees Fahrenheit or above temperatures with high humidity. Code Red can also be an indication of when the Air Quality Index is at an unhealthy level (151-200) for everyone. According to the Environmental Protection Agency, people may begin to experience health effects; members of sensitive groups may experience more serious health effects.

You, or someone you know, could be more at risk for heat-related illnesses if you:

  • Suffer from a medical condition.
  • Take certain prescription and non-prescription medicines. (Talk to your doctor and pharmacist to see if your medications can make you feel the heat more.)
  • Are over 50 or under five years old.
  • Are significantly overweight.
  • Have suffered from a heat-related illness before.
  • Drink alcohol.
  • Work in extremely hot conditions.
  • Are active.

During excessive heat, remember to check up on elderly or at-risk friends and neighbors. For help, call the Philadelphia Corporation for the Aging Senior Helpline at (215) 765-9040.

Heat-related illnesses

When the body cannot cool itself fast enough, its core temperature rises and heat-related illnesses can occur. Symptoms can range from mild dizziness to seizures. Below is a list of the most common heat related-illnesses.


Dehydration occurs when the body’s water level is low. This also causes certain chemicals in the body, such as salt and potassium, to fall. The main symptoms of dehydration include dizziness, lack of energy, dry mouth, and no appetite.


Sunburn makes the skin red, painful, and warm after sun exposure. Sunburn typically heals on its own in about a week. Severe sunburn may require medical attention.

Heat cramps

Heat cramps are muscle pains and spasms that occur during excessive physical activity. If you begin to suffer from a heat cramp, stop all physical activity to drink non-caffeinated fluids. Stretching or applying direct pressure to the affected area can also help. Heat cramps do not typically require emergency medical attention unless the pain and spasms are extreme. You should also seek medical attention for heat cramps if you are on a low sodium diet or suffer from heart problems.

Heat exhaustion          

Heat exhaustion is caused by excessive sweating that can occur after exercising or working in a hot, humid place. Symptoms of heat exhaustion include: sweating, pale and clammy skin, fatigue, headache, dizziness, shallow breaths, and a weak or rapid pulse.  If you are suffering from heat exhaustion, rest in a cool area, drink water or sports drinks, and elevate your feet on a stool or a chair. In severe cases, seek medical help. If not treated, heat exhaustion can cause heat stroke.

Heat stroke

Heat stroke—also called sunstroke—occurs when the body’s temperature control system stops working. During heat stroke, the body stops making sweat and skin can look flushed and feel hot or dry. Heat stroke can cause body temperature to rise to 106°F or higher within 10-15 minutes. This can cause death or permanent disability. Heat stroke victims may also become confused, have seizures, breathe shallowly, and have a weak or rapid pulse. Heat stroke is the most serious heat-related illness and people experiencing these symptoms should receive immediate medical attention. In an emergency, dial 911. While waiting for help, move a heat stroke victim to a cool area and remove most of their clothing. If possible, fan them or spray them with water.

Stay cool

During excessive heat, the Philadelphia Health Commissioner will send out a heat warning and set up Philadelphia’s Cooling Centers. To help stay cool during excessive heat, download the Stay Cool guide, visit cooling centers, use pools and spray grounds, or call the Philadelphia Heatline at (215) 765-9040 for advice on avoiding heat stress and referrals for emergency services.

Tips to stay cool:

  • Drink plenty of water. Avoid alcohol and caffeine.
  • Stay out of the sun. When in the sun, wear sunscreen (at least SPF 15).
  • Avoid working or playing outside between 10 a.m. and 2 p.m.
  • Do not leave children, pets, or individuals requiring special care in a parked car during periods of extreme heat.
  • Slow down. Rest in the shade or a cool place when you can.
  • Wear lightweight, light-colored, and loose-fitting clothes.
  • Wear a wide-brimmed hat or use an umbrella for shade.
  • Read your medication labels. Some medications can cause an adverse reaction in hot weather. Talk to your doctor or pharmacist if you need more information.
  • Use air conditioners and fans. If you use a fan, make sure your windows are open to release trapped hot air.
  • Use drapes, shades, louvers, or awnings in your home. Outdoor awnings or louvers can reduce the heat that enters the home by up to 80 percent.
  • Visit a friend with air conditioning or spend time in a cool place like a mall, library, or senior center.
  • Take a cool shower or bath.

You can use the Stay Cool Interactive Map to see all of the City’s cooling centers, spray grounds, and pools.

Cooling centers

Cooling Centers are only opened during an official Excessive Heat Warning. Before you visit a cooling center, call to make sure it’s open and if it has room for additional visitors. Use the Stay Cool Interactive Map to find the location, phone number, and hours of operation of nearby cooling centers. You can also use this list of Cooling Center Locations (PDF) for information.

Pools and spray grounds

Use the Stay Cool Interactive Map to find the location, phone number, and hours of operation of nearby pools and spray grounds. You can also use this list of the City’s pools and spray grounds (PDF) for information.

Private pool safety and requirements

The City has safety guides and requirements to make sure your pool, spa, or temporary kiddie pool is safe. Download the Swimming Pool and Spa Safety Guide (PDF) and view the Temporary Swimming Pool Requirements.