Heat Stress

Air Temperature (Degrees in fahrenheit) vs Relative Humidity

Relative Humidity  70 75 80 85 90 95 100 105 110
0% 64 69 73 78 83 87 91 95 99
10% 65 70 75 80 85 90 95 100 105
20% 66 72 77 82 87 93 99 105 112
30% 67 73 78 84 90 96 104 113 123
40% 68 74 79 86 93 101 110 122 137
50% 69 75 81 88 96 107 120 135 150
60% 70 76 82 90 100 114 132 149 n/a
70% 70 77 85 93 106 124 144 n/a n/a
80% 71 78 86 97 113 136 157 n/a n/a
90% 71 79 88 102 122 150 170 n/a n/a
100% 72 80 91 108 133 166 n/a n/a n/a

 

When is injury most likely to occur?

How to Use

  1. Located predicted high temperature across top axis-locate humidity along side axis.
  2. Intersect two readings to find the Apparent Temp or "what it feels like."

Heat Index 90-100

Sun stroke, heat cramps and heat exhaustion are possible with prolonged exposure and physical activity

Heat Index 101-129

Sun stroke, heat cramps and heat exhaustion are likely. Heat stroke is possible with prolonged exposure and physical activity.

Heat Index 120 - Higher

Heat stroke or sun stroke are imminent.