Based on the latest research findings, the NWS has devised the "Heat Index" (HI), (sometimes referred to as the "apparent temperature"). The HI, given in degrees Fahrenheit, is an accurate measure of how hot it really feels when the relative humidity (RH) is added to the actual air temperature.  

To find the Heat Index, look at the Heat Index Chart.  As an example, if the air temperature is 95°F (found on the left side of the table), and the relative humidity is 55% (found at the top of the table), the HI -- or how hot it really feels -- is 110°F.  This is at the intersection of the 95° row and the 55% column.  

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

Note on the HI chart the shaded zone above 105°F.  This corresponds to a level of HI that may cause increasingly severe heat disorders with continued exposure and/or physical activity.