To use the heat index charts, find the appropriate temperature at the top of
the chart. There are two charts on this page. Read down until you are opposite
the humidity/dewpoint. The number which appears at the intersection of the
temperature and humidity/dewpoint is the heat index.
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 temperature 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! |
For the more ambitious who would like to calculate the heat index, here is
the formula:
where:
HI = Heat Index
T = Temperature (° F)
RH = Relative Humidity (%)
Source: Meteorology for Scientists and Engineers, 2nd edition
by Roland B. Stull
Links to Other Heat Index Tables:
http://www.nsis.org/weather/heatindex.html
|
