-> I've seen these kinds of equations before. I am sure that Pat's English  
-> one is correct, and he made a typo in the metric one. That
"+" *should  
-> have been* a "*".  
  
To check this, I wrote the following little thing: 
  
------------------------------------------- 
  
INPUT "Temp (deg C)"; T 
INPUT "Windspeed (metres/sec)"; V 
  
W = 13.13 + .62 * T - 13.95 * V ^ .16 + .486 * T * V ^ .16 
IF W > T THEN W = T 
PRINT
">>>>>>>>>>>>>>>>>>>";
TAB(50); "Windchill: "; W; "deg. C." 
  
PRINT "Fahrenheit temp:"; 
T = 1.8 * T + 32 
PRINT T; "deg. F" 
  
PRINT "Windspeed in miles per hour:"; 
V = V * 2.237 
PRINT V; "mph" 
  
W = 35.74 + .6215 * T - 35.75 * V ^ .16 + .4275 * T * V ^ .16 
IF W > T THEN W = T 
PRINT "Windchill: "; W; "deg. F., 
>>>>>>>>>"; 
  
W = (W - 32) / 1.8 
PRINT TAB(50); "which is:   "; W; "deg. C" 
PRINT 
END 
  
----------------------------------------------------------- 
  
Pat's two formulae are in there, as he wrote them except that I 
corrected the typo in the metric one. 
  
I found, by trial and error, that the metric one expects the windspeed 
in metres per second, and the "English" one in miles per hour. (I tried 
km/h, ft/sec, knots, and various others before I found the ones that 
worked.) In these units, the agreement is very good. The windchills 
always agree to within a very small fraction of a degree. 
  
                       dow 
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