Heat
Index
Chart
Air Temperature (Degrees F)
70 75 80 85 90 95 100 105 110 115 120
Relative
Humidity
Apparent
Temperature
0% 64 69 73 78 83 87 91 95 99 103 107
10% 65 70 75 80 85 90 95 100 105 111 116
20% 66 72 77 82 87 93 99 105 112 120 130
30% 67 73 78 84 90 96 104 113 123 135 148
40% 68 74 79 86 93 101 110 123 137 151  
50% 69 75 81 88 96 107 120 135 150    
60% 70 76 82 90 100 114 132 149      
70% 70 77 85 93 106 124 144        
80% 71 78 86 97 113 136 157        
90% 71 79 88 102 122 150 170        
100% 72 80 91 108 133 166          
The Heat Index shows the effects of the combination of heat and humidity. The apparent tempertaure is the heat your body thinks it is. To use the chart locate the temperature along the top row and the humidity along the left hand column. Where the two intersect is the current heat index. It's usually hotter than you think!