Apparent Temperature


Chart


     REL                    TEMPERATURE(degF)
     HUM(%)   70  75  80  85  90  95 100 105 110 115 120 125 130 135
     ---     --- --- --- --- --- --- --- --- --- --- --- --- --- ---
       0      64  69  73  78  83  87  91  95  99 103 107 111 117 120
       5      64  69  74  79  84  88  93  97 102 107 111 116 122 126
      10      65  70  75  80  85  90  95 100 105 111 116 123 131
      15      65  71  76  81  86  91  97 102 108 115 123 131
      20      66  72  77  82  87  93  99 105 112 120 130 141
      25      66  72  77  83  88  94 101 109 117 127 139
      30      67  73  78  84  90  96 104 113 123 135 148
      35      67  73  79  85  91  98 107 118 130 143
      40      68  74  79  86  93 101 110 123 137 151
      45      68  74  80  87  95 104 115 129 143
      50      69  75  81  88  96 107 120 135 150
      55      69  75  81  89  98 110 126 142
      60      70  76  82  90 100 114 132 149
      65      70  76  83  91 102 119 138
      70      70  77  84  93 106 124 144
      75      70  77  85  95 109 130 150
      80      71  78  86  97 113 136
      85      71  78  87  99 117 140
      90      71  79  88 102 122 150
      95      71  79  89 105 126
     100      72  80  90 108 131

	

Explanation

      The apparent temperature is a measure of relative discomfort due
 to combined heat and high humidity.  It was developed by R.G. Steadman
 (1979) and is based on physiological studies of evaporative skin
 cooling for various combinations of ambient temperature and humidity.
 The apparent temperature equals the actual air temperature when the
 dew-point temperature is 57.2F (14C).  At higher dew-points, the
 apparent temperature exceeds the actual temperature and measures the
 increased physiological heat stress and discomfort associated with
 higher than comfortable humidities.  When the dew-point is less than
 57.2F, on the other hand, the apparent temperature is less than the
 actual air temperature and measures the reduced stress and increased
 comfort associated with lower humidities and greater evaporative skin
 cooling.

      Apparent temperatures greater than 80 F are generally associated
 with some discomfort.  Values approaching or exceeding 105 F are
 considered life-threatening, with severe heat exhaustion or heatstroke
 possible if exposure is prolonged or physical activity high.  The
 degree of heat stress may vary with age, health, and body
 characteristics.


	

Apparent Temperature Chart and Explanation courtesy of the Climate Analysis Center