Windchill Calculator (NOAA)

Given the true outdoor temperature in degrees Fahrenheit and the wind speed in statute miles per hour, this program will compute the theoretical windchill temperature according to the NOAA formula.  The formula pertains to a worst-case nighttime scenario with no solar influence.

Temperature (−45 to +40) =  °F            Wind Speed (5 to 60) =  (mi / h)         

Theoretical windchill temperature  =  +36° F


The NOAA Formula:

Let:
= True outdoor temperature in degrees Fahrenheit.
W = Wind speed in statute miles per hour.

Then:
Windchill °F  =  35.74  +  0.6215 × F  -  35.75 × W 0.16  +  0.4275 × F × W 0.16




Windchill Table     ( F = Temperature in degrees Fahrenheit,    W = Wind speed in statute miles per hour )
Table Format A
   F +40 +35 +30 +25 +20 +15 +10  +5   0  -5 -10 -15 -20 -25 -30 -35 -40 -45 F   
 W                                                                             W 
 5   +36 +31 +25 +19 +13  +7  +1  -5 -11 -16 -22 -28 -34 -40 -46 -52 -57 -63   5 
 10  +34 +27 +21 +15  +9  +3  -4 -10 -16 -22 -28 -35 -41 -47 -53 -59 -66 -72  10 
 15  +32 +25 +19 +13  +6   0  -7 -13 -19 -26 -32 -39 -45 -51 -58 -64 -71 -77  15 
 20  +30 +24 +17 +11  +4  -2  -9 -15 -22 -29 -35 -42 -48 -55 -61 -68 -74 -81  20 
 25  +29 +23 +16  +9  +3  -4 -11 -17 -24 -31 -37 -44 -51 -58 -64 -71 -78 -84  25 
 30  +28 +22 +15  +8  +1  -5 -12 -19 -26 -33 -39 -46 -53 -60 -67 -73 -80 -87  30 
 35  +28 +21 +14  +7   0  -7 -14 -21 -27 -34 -41 -48 -55 -62 -69 -76 -82 -89  35 
 40  +27 +20 +13  +6  -1  -8 -15 -22 -29 -36 -43 -50 -57 -64 -71 -78 -84 -91  40 
 45  +26 +19 +12  +5  -2  -9 -16 -23 -30 -37 -44 -51 -58 -65 -72 -79 -86 -93  45 
 50  +26 +19 +12  +4  -3 -10 -17 -24 -31 -38 -45 -52 -60 -67 -74 -81 -88 -95  50 
 55  +25 +18 +11  +4  -3 -11 -18 -25 -32 -39 -46 -54 -61 -68 -75 -82 -89 -97  55 
 60  +25 +17 +10  +3  -4 -11 -19 -26 -33 -40 -48 -55 -62 -69 -76 -84 -91 -98  60 
 W                                                                             W 
   F +40 +35 +30 +25 +20 +15 +10  +5   0  -5 -10 -15 -20 -25 -30 -35 -40 -45 F   
 

This is the same format as the table on the NOAA web site.  Note that the progression of the temperature values increases positively to the left and negatively to the right.  This is opposite to the convention of the standard (X-axis) number line where negative is to the left and positive is to the right.  This odd convention may seem uncomfortable to some people, so there is the alternative Table Format B below, which may feel more comfortable.  It is the same information, only the sequential column order is inverted.


Reference:
http://www.nws.noaa.gov/om/windchill/
Windchill Table     ( F = Temperature in degrees Fahrenheit,    W = Wind speed in statute miles per hour )
Table Format B
   F -45 -40 -35 -30 -25 -20 -15 -10  -5   0  +5 +10 +15 +20 +25 +30 +35 +40 F   
 W                                                                             W 
 5   -63 -57 -52 -46 -40 -34 -28 -22 -16 -11  -5  +1  +7 +13 +19 +25 +31 +36   5 
 10  -72 -66 -59 -53 -47 -41 -35 -28 -22 -16 -10  -4  +3  +9 +15 +21 +27 +34  10 
 15  -77 -71 -64 -58 -51 -45 -39 -32 -26 -19 -13  -7   0  +6 +13 +19 +25 +32  15 
 20  -81 -74 -68 -61 -55 -48 -42 -35 -29 -22 -15  -9  -2  +4 +11 +17 +24 +30  20 
 25  -84 -78 -71 -64 -58 -51 -44 -37 -31 -24 -17 -11  -4  +3  +9 +16 +23 +29  25 
 30  -87 -80 -73 -67 -60 -53 -46 -39 -33 -26 -19 -12  -5  +1  +8 +15 +22 +28  30 
 35  -89 -82 -76 -69 -62 -55 -48 -41 -34 -27 -21 -14  -7   0  +7 +14 +21 +28  35 
 40  -91 -84 -78 -71 -64 -57 -50 -43 -36 -29 -22 -15  -8  -1  +6 +13 +20 +27  40 
 45  -93 -86 -79 -72 -65 -58 -51 -44 -37 -30 -23 -16  -9  -2  +5 +12 +19 +26  45 
 50  -95 -88 -81 -74 -67 -60 -52 -45 -38 -31 -24 -17 -10  -3  +4 +12 +19 +26  50 
 55  -97 -89 -82 -75 -68 -61 -54 -46 -39 -32 -25 -18 -11  -3  +4 +11 +18 +25  55 
 60  -98 -91 -84 -76 -69 -62 -55 -48 -40 -33 -26 -19 -11  -4  +3 +10 +17 +25  60 
 W                                                                             W 
   F -45 -40 -35 -30 -25 -20 -15 -10  -5   0  +5 +10 +15 +20 +25 +30 +35 +40 F   
 

In this table format, the temperature values follow the convention of the standard (X-axis) number line where negative is to the left and positive is to the right.


Jay Tanner - 2017