Category : Science and Education
Archive   : CHILLDOC.ZIP
Filename : CHILL

Wind Chill Index

A very strong wind combined with a temperature slightly below freezing
can have the same chilling effect as a temperature nearly 50 degrees lower
in a calm atmosphere. Arctic explorers and military experts have developed
what is called the wind-chill factor, which shows the combined effects of
wind and temperature as equivalent calm-air temperatures ("Calm-air" as used
in wind-chill determinations actually refers to the conditions created by a
person walking briskly (at 4 miles-per-hour) under calm wind conditions.).
In effect, the index describes the cooling power of the air on exposed
flesh. The wind-chill table below shows this cooling power for various
combinations of wind and temperature, and will help you gauge how much
protection you really need.

To determine the wind-chill, find the outside air temperature on the
top line, then read down the column to the measured wind speed. For example:
When the outside air temperature is zero degrees, and the wind speed is 20
miles per hour, the rate of heat loss is equivalent to minus 40 degrees
under calm conditions.


Equivalent Temperature

Calm 35 30 25 20 15 10 5 0 -5 -10 -15 -20 -25 -30

W 5 32 27 22 16 11 6 0 -5 -10 -15 -21 -26 -31 -36
i
n 10 22 16 10 3 -3 -9 -15 -22 -27 -34 -40 -46 -52 -58
d
15 16 9 2 -5 -11 -18 -25 -31 -38 -45 -51 -58 -65 -72
S
p 20 12 4 -3 -10 -17 -24 -31 -39 -46 -53 -60 -67 -74 -81
e
e 25 8 1 -7 -15 -22 -29 -36 -44 -51 -59 -66 -74 -81 -88
d
30 6 -2 -10 -18 -25 -33 -41 -49 -56 -64 -71 -79 -86 -93
m
p 35 4 -4 -12 -20 -27 -35 -43 -52 -58 -67 -74 -82 -89 -97
h
40 3 -5 -13 -21 -29 -37 -45 -53 -60 -69 -76 -84 -92 -100

45 2 -6 -14 -22 -30 -38 -46 -54 -62 -70 -78 -85 -93 -102