Originally Posted by

**King_O_Hill**
OK, just to give a little in-depth explanation:

The yahoo feed for what we refer to as "Real Feel" is pulled from the "Wind" condition. Specifically the "Chill" element of it.

Here is the call from UniAW.js:

obj.realFeel = findChild(effectiveRoot, "yweather:wind").getAttribute("chill");

Here is the Yahoo feed explanation:

yweather:wind

Forecast information about wind.

Attributes:

chill: wind chill in degrees (integer)

direction: wind direction, in degrees (integer)

speed: wind speed, in the units specified in the speed attribute of the yweather:units element (mph or kph). (integer)

This is the response from Yahoo:

<yweather:wind chill="69" direction="0" speed="0"/>

So, as you can see, there isn't any way to get a "Heat Index", as it doesn't exist in the feed.

Ian, I would suggest changing the "Real Feel" label to "Chill". This might help eliminate any future confusion.

If you would like to calculate the heat index,

HI = -42.379 + 2.04901523*T + 10.14333127*RH - .22475541*T*RH - .00683783*T*T - .05481717*RH*RH + .00122874*T*T*RH + .00085282*T*RH*RH - .00000199*T*T*RH*RH

Where T is temperature in degrees F and RH is relative humidity in percent.

HI is the heat index expressed as an apparent temperature in degrees F.

If the RH is less than 13% and the temperature is between 80 and 112 degrees F, then the following adjustment is subtracted from HI:

ADJUSTMENT = [(13-RH)/4]*SQRT{[17-ABS(T-95.)]/17}

ABS and SQRT are the absolute value and square root functions, respectively.

On the other hand, if the RH is greater than 85% and the temperature is between 80 and 87 degrees F, then the following adjustment is added to HI:

ADJUSTMENT = [(RH-85)/10] * [(87-T)/5]

I have this coded for js, but I'm not going to post it here unless someone is really interested.