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Heat Index Chart - Relative Humidity vs. Air Temperature

As one who is severely discomforted by a combination of heat and humidity, this kind of table is of great interest. If I am going to be miserable, I want to know exactly how miserable I really am! This information is derived from NOAA Click here for a windchill chart.




Extreme Danger - Heat stroke or sun stroke likely
Danger - Sunstroke, muscle cramps and/or heat exhaustion likely
Extreme Caution - Sunstroke, muscle cramps and/or heat exhaustion possible
Caution - Fatigue possible




NOAA provides the following equation for calculating heat index:
       HI = -42.379 + 2.04901523T + 10.14333127R - 0.22475541TR - 6.83783x10-3T2
              
- 5.481717x10-2R2 + 1.22874x10-3T2R + 8.5282x10-4TR2 - 1.99x10-6T2R2,

           where T = ambient dry bulb temperature (°F) R = relative humidity (integer percentage)

      "Because this equation is obtained by multiple regression analysis, (HI) has an error of ±1.3°F"
 

Air
Temp
(°F)
Relative Humidity (%)
 404550556065707580859095100
110136            
108130137           
106124130137          
104119124131137         
102114119124130137        
100109114118124129136       
98105109113117123128134      
96101104108112116121126132     
9497100102106110114119124129136   
92949699101105108112116121126131  
9091939597100103106109113117122127132
88888991939598100103106110113117121
868587888991939597100102105108112
848384858688899092949698100103
8281828384848586888990919395
8080808181828283848485868687

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