Understanding Marine Weather – Wind Chill
Source: Mariners Learning System
By Captain Bob Figular
Just as there are persistent hot places around the world, there are persistent cold places. The cold air alone can be deadly but when the air is moving it feels much colder. The wind chill is the effect of the wind on people and animals. The wind chill temperature is based on the rate of heat loss from exposed skin caused by wind and cold and is to give you an approximation of how cold the air feels on your body.
As the wind increases, it removes heat from the body, driving down skin temperature and eventually the internal body temperature. If the temperature is 0°F and the wind is blowing at 15 mph, the wind chill temperature is -19°F. At this level, exposed skin can freeze in just a few minutes.
The only effect wind chill has on inanimate objects, such as car radiators and water pipes, is to shorten the amount of time for the object to cool. The inanimate object will not cool below the actual air temperature. For example, if the temperature outside is -5°F and the wind chill temperature is -31°F, then your car’s radiator temperature will be no lower than the air temperature of -5°F.
The Wind Chill Chart
To determine the wind chill temperature, find the value closest to your outside air temperature. Find the value that most closely represents your present wind speed. Your wind chill temperature is the value where lines drawn from the air temperature and wind cross.
| WIND (mph) |
Temperature (°F) |
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|
|
|
|
|
|
|
|
|
|
|
| |
40 |
35 |
30 |
25 |
20 |
15 |
10 |
5 |
0 |
-5 |
-10 |
-15 |
-20 |
-25 |
-30 |
-35 |
| 0 |
40 |
35 |
30 |
25 |
20 |
15 |
10 |
5 |
0 |
-5 |
-10 |
-15 |
-20 |
-25 |
-30 |
-35 |
| 5 |
37 |
31 |
25 |
19 |
13 |
7 |
1 |
-5 |
-11 |
-16 |
-22 |
-28 |
-34 |
-40 |
-46 |
-52 |
| 10 |
34 |
27 |
21 |
15 |
11 |
3 |
-4 |
-10 |
-16 |
-22 |
-28 |
-35 |
-41 |
-47 |
-53 |
-59 |
| 15 |
32 |
25 |
19 |
13 |
6 |
0 |
-7 |
-13 |
-19 |
-26 |
-32 |
-39 |
-45 |
-51 |
-58 |
-64 |
| 20 |
30 |
24 |
17 |
11 |
4 |
-2 |
-9 |
-15 |
-22 |
-29 |
-35 |
-42 |
-48 |
-55 |
-61 |
-68 |
| 25 |
29 |
23 |
16 |
9 |
3 |
-4 |
-11 |
-17 |
-24 |
-31 |
-38 |
-44 |
-51 |
-58 |
-64 |
-71 |
| 30 |
28 |
22 |
15 |
8 |
1 |
-6 |
-12 |
-19 |
-26 |
-33 |
-39 |
-46 |
-53 |
-60 |
-67 |
-73 |
| 35 |
28 |
21 |
14 |
7 |
0 |
-7 |
-14 |
-21 |
-27 |
-34 |
-41 |
-48 |
-55 |
-62 |
-69 |
-76 |
| 40 |
27 |
20 |
13 |
6 |
-1 |
-8 |
-15 |
-22 |
-29 |
-36 |
-43 |
-50 |
-57 |
-64 |
-71 |
-78 |
What is important about the wind chill besides feeling colder than the actual air temperature? The lower the wind chill temperature, the greater you are at risk for developing frost bite and/or hypothermia.
Frostbite occurs when your body tissue freezes. The most susceptible parts of the body are fingers, toes, ear lobes, and the tip of the nose. Hypothermia occurs when body core temperature, normally around 98.6°F falls below 95°F.
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