From June to September the state of Arizona and specifically Maricopa County experiences deceptively dangerous temperatures. Because it is not like a blizzard, where one can look outside and see the severity of the weather, many Arizonans are often unprepared to deal with our heat.

The National Weather Service has studied weather conditions in many areas of the country and has developed a formula that takes into account factors such as temperature, humidity, amount of cloudiness and expected duration of heat. These factors together help to tell the forecasters when a potentially life threatening heat emergency will take place.

What is it that makes a very hot day a "heat emergency?” It is much more than just a high temperature.

Below are the definitions you should know:

HEAT ADVISORY:	When the temperature is forecast to be unusually hot but not life-threatening.
HEAT WATCH:	When a life-threatening heat emergency may occur in the next 24-48 hours.
HEAT WARNING:	When a life-threatening emergency exists or is imminent.