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 Heat

Safety Tips for Concerning Children

  • Make sure your child's safety seat and safety belt buckles aren't too hot before securing your child in a safety restraint system, especially when your car has been parked in the heat.
  • Never leave your child unattended in a vehicle, even with the windows down.
  • Teach children not to play in, on, or around cars.
  • Always lock car doors and trunks--even at home--and keep keys out of children's reach.
  • Always make sure all children have left the car when you reach your destination. Don't leave sleeping infants in the car ever

Safety Tips for Adults

  • Slow down. Reduce, eliminate or reschedule strenuous activities until the coolest time of the day. Children, seniors and anyone with health problems should stay in the coolest available place, not necessarily indoors.
  • Dress for summer. Wear lightweight, light-colored clothing to reflect heat and sunlight.
  • Put less fuel on your inner fires. Foods, like meat and other proteins that increase metabolic heat production also increase water loss.
  • Drink plenty of water, non-alcoholic and decaffeinated fluids. Your body needs water to keep cool. Drink plenty of fluids even if you don't feel thirsty. Persons who have epilepsy or heart, kidney or liver disease, are on fluid restrictive diets or have a problem with fluid retention should consult a physician before increasing their consumption of fluids. Do not drink alcoholic beverages and limit caffeinated beverages.
  • During excessive heat periods, spend more time in air-conditioned places. Air conditioning in homes and other buildings markedly reduces danger from the heat. If you cannot afford an air conditioner, go to a library, store or other location with air conditioning for part of the day.
  • Don't get too much sun. Sunburn reduces your body's ability to dissipate heat.
  • Do not take salt tablets unless specified by a physician. 

Heat Index

The Heat Index, sometimes referred to as the apparent temperature is given in degrees Fahrenheit. The Heat Index is a measure of how hot it really feels when relative humidity is factored in with the actual air temperature.

To find the Heat Index temperature, look at the Heat Index chart below. As an example, if the air temperature is 96°F and the relative humidity is 65%, the heat index--how hot it feels--is 121°F. The National Weather Service will initiate alert procedures when the Heat Index is expected to exceed 105°-110°F (depending on local climate) for at least 2 consecutive days.

heat index table

IMPORTANT: Since heat index values were devised for shady, light wind conditions, exposure to full sunshine can increase heat index values by up to 15°F. Also, strong winds, particularly with very hot, dry air, can be extremely hazardous.

The Heat Index Chart shaded zone above 105°F (orange or red) shows a level that may cause increasingly severe heat disorders with continued exposure or physical activity.

Never Leave Children, Disabled Adults or Pets in Parked Vehicles

Each year, dozens of children and untold numbers of pets left in parked vehicles die from hyperthermia. Hyperthermia is an acute condition that occurs when the body absorbs more heat than it can handle. Hyperthermia can occur even on a mild day. Studies have shown that the temperature inside a parked vehicle can rapidly rise to a dangerous level for children, pets and even adults.  Leaving the windows slightly open does not significantly decrease the heating rate. The effects can be more severe on children because their bodies warm at a faster rate than adults.

heatstroke deaths

Courtesy of San Francisco State University. Use of this graph does not imply NWS endorsement of services provided by San Francisco State University.

How Fast Can the Sun Heat a Car?

The sun's shortwave radiation (yellow in figure below) heats objects that it strikes.  For example, a dark dashboard or seat can easily reach temperatures in the range of 180 to over 200°F. These objects (e.g., dashboard, steering wheel, child seat) heat the adjacent air by conduction and convection and also give off longwave radiation (red in figure below) which is very efficient at warming the air trapped inside a vehicle.

The atmosphere and the windows of a car are relatively transparent to the sun’s shortwave radiation (yellow in figure above) and are warmed little. This shortwave energy, however, does heat objects it strikes. For example, a dark dashboard or seat can easily reach temperatures in the range of 180°F to more than 200°F. These objects, e.g., dashboard, steering wheel, childseat, heat the adjacent air by conduction and convection and give off longwave radiation (infrared), which efficiently warms the air trapped inside a vehicle. Learn more about excessive heat and cars.

boy back seat girl back seat

 

 Normal Temperatures of Puerto Rico and U.S. Virgin Islands for August, September and October

Maximum Temperatures Minimum Temperatures
August August
September September
October October
  

Heat Awareness Day

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  Concientizacion sobre calor extremo

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Heat Awareness

Concienciacion sobre el Calor

NOTE: NWS San Juan in collaboration with University of Puerto Rico/Medical Sciences Campus/Department of Enviromental Health and University of Puerto Rico/Carolina Campus/Department of Natural Sciences have been working since July 2012 on a couple of research papers about Heat Wave Frequency and Health Consequences in Puerto Rico. The main goal of these local studies is to determine local criteria for Heat Warnings and/or Advisories.

NWS's Heat Safety webpage

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