Miami hasn't had just one hot day this year, but rather weeks and weeks of intense heat.<br />In fact, CNN reports seven of the 10 hottest weeks on record have occurred this year -- and temperatures usually don't peak until the beginning of August.<br />On Tuesday, the temperature at Miami International Airport reached 98 degrees Fahrenheit, but no heat advisories or excessive heat warnings were issued.<br />On the same day, a high temperature of 91 degrees was recorded in Topeka, Kansas, and a heat advisory was issued. Yet 91 degrees is cooler than 96 degrees!<br />Turns out, every National Weather Service (NWS) office has different criteria for heat advisories and excessive heat warnings.<br />The NWS takes into account a region's topography, climatology and potential urban heat island effects.<br />And while some offices use the heat index measurement, others use the 'wet bulb globe reading,' which takes into account sun angle, cloud cover, and wind speed.