Wind Chill Calculation

[Randall75]

Hi Stu and gang
 I would like to see WeatherCat Calculate the Windchill in real time not calculated from a  ten minute wind speed  average for now it just gets the reading from the VP console which calculates it from the 10 minute wind speed average the competitors out there Weather Tracker and Weather Snoop calculates it in real time as soon as the wind speed is over 4 MPH and temperature is below 50 degrees


thanks


cheers


 

[mcrossley]

I thought the usual standard is to calculate wind chill from an averaged value is it not? If you use the latest speed the wind chill will vary wildly with gusts and lulls, the idea is that wind chill gives you an idea of sustained heat loss from the human body.

[Randall75]

Hi Stu,Mark, and WC users
 I guess that is the norm that the wind chill is calculated on a 10 minute wind speed average
But my LaCrosse 2315 that i have had for about 11 years always calculated it when the wind was 4 MPH or higher and the temperature was at 50 degrees or less and that is what I am used to
Now that I have a Davis VP2 Plus and it uses an average  wind speed to calculate the wind chill just use to having it done in real time Even at Wunderground they calculate it when the wind is 4 MPH or more
also the National Weather Service calculates it this way


cheers


 

[mcrossley]

They still use below 50?F and above 4 mph (or 3 mph for some newer calculations), but use the current 10 minute average speed at that point in time. They do not wait for 10 minutes after the criteria are met, or am I misunderstanding? Some met office standards seem to use a 2 or 3 minute minute average rather than 10, but I think they all use some sort of averaged speed.

[Randall75]

Hi Mark

Stu

as you know WeatherCat is channel based, so when you select a channel from your station for a gauge it passes that value through - it doesn't calculate it - the wind chill gauge is driven directly from the windchill channel from the station driver. On a Vantage or Vue this is based on the 10-minute average as it more accurately reflects how it will feel outside to a human. Davis has this to say:'The reason an average wind speed is employed in the Vantage Pro and Vantage Pro2 to calculate wind chill is as follows: The human body has a high heat capacity, thus high wind speeds have no effect on the body's thermal equilibrium. So, an average wind speed provides a more accurate representation of the body's response than an instantaneous reading. Also, "official" weather reports (from which wind chill is calculated) provide average wind speed, so using an average wind speed more closely matches the results that are seen in weather reports.'.

I just don't like a 10 minute wind average calculation but I guess I'm stuck with it


cheers


 

[WCDev]

I've raised it as a feature request Randall, probably as a tick-box somewhere in the preferences.