Terms to Know

Heat Wave: At least 3 days of abnormally high heat (90 degrees Fahrenheit or higher) and high uncomfortable humidity (80% relative humidity or higher) are expected.

Heat Index: A number in degrees Fahrenheit that tells how hot it really feels when relative humidity is added to the actual air temperature. Exposure to full sunshine can increase the heat index by 15 degrees. It is also known as the "Apparent Temperature"

Excessive Heat Watch: Heat watches are issued when conditions are favorable for an excessive heat event in the next 24 to 72 hours. A Watch is used when the risk of a heat wave has increased but its occurrence and timing is still uncertain.

Excessive Heat Warning: An Excessive Heat Warning is issued within 12 hours of the onset of extremely dangerous heat conditions. The general rule of thumb for this Warning is when the maximum heat index temperature is expected to be 105° or higher for at least 2 days and night time air temperatures will not drop below 75°.

Heat Advisory: A Heat Advisory is issued within 12 hours of the onset of extremely dangerous heat conditions. A heat advisory is issued when maximum daytime heat index values are forecast to reach 100 to 104°F for at least 2 consecutive hours.

*Note: For New York City, a Heat Advisory is issued when the heat index is forecast to reach 95 to 99F for at least 2 consecutive days or 100 to 104F for any length of time.

Excessive Heat Outlooks: These are issued when the potential exists for an excessive heat event in the next 3-7 days. An Outlook provides information to those who need considerable lead-time to prepare for the event.

UV Index: A rough measure of the amount of harmful ultraviolet radiation in the sunlight reaching the Earth's surface at a given location, given the time of year and current atmospheric conditions, expressed in terms of the risks that are associated with exposure to that amount of radiation.


Heat Health Hazards

Heat Stroke: This condition is also known as sunstroke, which can be life threatening. Body temperature can rise and cause brain damage; death may result if not cooled quickly. Signals include hot, red and dry skin; changes in consciousness; rapid, weak pulse, and shallow breathing. Relief for lowering body temperature can be with a cold bath or sponge.

Heat Exhaustion: This condition is less dangerous than heat stroke. It usually occurs when people exercise too heavily or work in warm, humid places where body fluids are lost. Signals include cool, moist, pale or flushed skin; heavy sweating; headache; nausea or vomiting; dizziness and exhaustion. If symptoms occur, get the victim out of sun, and apply cool, wet cloths.

Sunburn: Redness and pain; in severe cases, swelling of skin, blisters, fever, and headaches. Sunburn slows the skin's ability to cool itself. Ointments can be a relief for pain in mild cases. A physician should see serious cases.

Heat Cramps: Heat cramps are muscular pains and spasms caused by heavy exertion. Signals are abdominal and leg muscle pain. Loss of water and salt from sweating causes cramping. Relief can be firm pressure on cramping muscles, or gentle massages to relieve cramping.

Heat Rashes: Heat rashes are a common problem resulting from persistent wetting of clothing by unevaporated sweat.

Act (during a High Heat Event)

General Safety Tips
  • Slow down on strenuous activity and exercise, especially during the sun's peak hours: 11 a.m. to 4 p.m.
  • Exercise should be done in the early morning between 4 to 7 a.m.
  • Eat less protein and more fruits and vegetables. Protein produces and increases metabolic heat, which causes water loss. Eat small meals but eat more often. 
  • Heavy sweating removes salt and minerals from the body. These are necessary for your body and must be replaced. The easiest and safest way to do this is through your diet, have water and snacks. Drink fruit juice or a sports beverage when you exercise or work in the heat.
  • If possible, stay out of the sun and stay in air-conditioning. Sunburn slows the skin's ability to cool itself. The sun will also heat the inner core of your body, resulting in dehydration. If you must go outdoors, wear sunscreen with a high sun protector factor rating (at least SPF 15) and a hat to protect your face and head.
  • Dress appropriately. When outdoors, wear loose-fitting, lightweight, light-colored clothing that will cover as much skin as possible. Lightweight, light-colored clothing reflects the heat and sunlight and helps maintain normal body temperature. Cover as much skin as possible to avoid sunburn and over-warming effects of sunlight on your body.
  • Stay indoors as much as possible. If air conditioning is not available, stay on the lowest floor, out of the sunshine. Even in the warmest weather, staying indoors, out of the sunshine, is safer than long periods of exposure to the sun.
  • If your home is not air-conditioned, go to a public building with air conditioning each day for several hours. Air-conditioned locations are the safest places during extreme heat because electric fans do not cool the air. Fans do help sweat evaporate, which gives a cooling effect.
  • Drink plenty of fluids, particularly water (at least 2-4 glasses of water per hour during extreme heat), even if you do not feel thirsty. Your body needs water to keep cool. Avoid beverages containing alcohol or caffeine.
  • Avoid using salt tablets unless directed to do so by a physician. Salt causes the body to retain fluids, resulting in swelling. Salt affects areas of your body that help you sweat, which would keep you cool. Persons on salt-restrictive diets should check with a physician before increasing salt intake.
  • Never leave children in a parked car or vehicle during periods of intense summer heat. Temperatures inside a closed vehicle can reach over 140 degrees Fahrenheit quickly. Exposure to such high temperatures can kill within a matter of minutes.
  • Strenuous activities should be reduced, eliminated or rescheduled to the coolest time of the day. Make sure that children get lots of rest when they are active. Heat can make children feel tired.
  • Make sure children are well-hydrated and provide them drinking water regularly, even before they ask for it.
  • If your home does not have air-conditioning, find a nearby building that does. Libraries can be a great place for a cool retreat from the heat.
  • Infants and children up to four years of age are especially sensitive to the effects of high temperatures. They rely on others to regulate their environments and provide adequate liquids.
Older Adults 
  • People who are 65 years of age or older may not compensate for heat stress efficiently and are less likely to sense and respond to change in temperature.
  • Older adults don't 'feel the heat' the way younger people do, and so might not be aware of the risks of high temperatures.
  • Older adults can have chronic medical conditions that changes normal body responses to heat.
  • Be aware that prescription medicines can impair the body's ability to regulate its temperature or inhibit perspiration.
  • Never leave your pet in a parked car or vehicle during periods of intense summer heat, not even for a minute. Temperatures inside a closed vehicle can reach over 140 degrees Fahrenheit quickly. Exposure to such high temperatures can kill within a matter of minutes.
  • Be aware that asphalt can get very hot and burn your pet's paws - walk pets on the grass when possible.
  • Make sure there is enough water and food for pets and limit their exercise.
  • Don't rely on a fan.  Animals respond differently to heat than humans do, and fans don't cool off pets as effectively as they do people.
  • Check on animals frequently to ensure that they are not suffering from the heat.
  • Any time your pet is outside, ensure they have water and a shady place to rest.
  • Cats and dogs can get sunburn. Cats with white ears are prone to develop sunburn on the tips and edges of the ears. Dogs that are hairless or dogs with light colored fur can develop sunburn. Dogs with pink noses are also susceptible to the effects of sunburn.
Functional Needs
  • Those who are physically ill, especially with heart disease or high blood pressure, or who take certain medications for conditions such as depression, insomnia or poor circulation, may be affected by extreme heat.
  • Visit at least twice a day and closely watch for signs of heat exhaustion or heat stroke.

Additional Tips

Household Chores
  • Heat-producing and moisture-producing jobs such as cooking, cleaning, ironing and laundry should be done during cooler, early morning and evening hours.
  • Air-dry dishes instead of the dishwasher’s heat drying cycle.
  • Avoid unnecessary trips in and out of the house, especially on very hot days.  Heat and humidity come in each time you open the door.
Energy Conservation
  • Power outages are more likely to occur during warm weather when utility usage is at its peak.  To avoid putting a strain on the power grid, conserve energy when possible to help prevent power disruptions.
  • Set the air conditioner thermostat no lower than 78 degrees.
  • Only use the air conditioner when home.  If you want to cool your home before you return, set a timer to have it switch on no more than a half-hour before you arrive.
  • Use portable or ceiling fans; mild air movement of 1 MPH can make the room feel 3 to 4 degrees cooler.
  • In warm weather, run ceiling fans counterclockwise so airflow under the fan will push down and create a wind-chill effect.  Running the fan in a clockwise direction creates a gentle updraft, but recirculates heat down.
  • On hot days, avoid using the oven; cook on the stove, use a microwave oven, or grill outside.
  • Turn non-essential appliances off.  Unplug appliances and electronics when not in use.
  • Plug home electronics, such as TVs, DVD players and computers into power strips and turn off the power strips when the equipment is not in use.
  • Minimize indoor heat by only using appliances that have heavy electrical loads early in the morning or very late at night.