There are tables but the extrapolation relies on exponents. I don’t understand why simple exponents are not part of the expressions outside of exponenting a constant. There is xEy but that is x time 10 to the y
@BIELITZ do you have the source for your original formula?
Also. This became much more fun but may be more than an evening and a deep maths delve into some basic lacks of the expressions and can we, as a team work around them?
The National Weather Service’s formula to calculate wind chill is: 35.74 + 0.6215T – 35.75(V^0.16) + 0.4275T(V^0.16).
That’s Fahrenheit for some really obscure reason but end result is easily converted.
I have to admit to being defeated on this one without basic exponent ability within the expressions of x^y.
Maybe @Facer_Official knows something I don’t as to why there is no ability to square, cube or do basic exponentials in the expressions. Maybe there is and it is just not documented?
That one still uses to the power of 0.16 and there is no power of in the facer expressions.
Sorry for the delay. 22 police 7 indoors, 2 with riot gear. Paramedics cleared the combatants as OK but both fight drunk in the house downstairs from my room. I tried to offer bottled water but…
Maybe you can try to use the Australian model for “Apparent temperature”, which also integrates humidity, but uses only operations that we have available in Facers tools set.
It produces slightly different results at some extremes like complete calm but, maybe it is worth a try. It also should work with different temperature array than the Wind chill, which is meant to work best with temperatures close to and below freezing point. You can compare results of the “Wind chill index” by inserting same test values into both calculators.
Hi all
For one, it only makes sense to talk about a chill factor when you have 10°C or less. So that may be a condition you want to consider.
There is an easier formula which is good enough. It is based on a few assumptions, such as being at sea level and humidity is not factored in either.
Formula for Celsius and speed as Kmh:
wind chill = 13.12 + (0.6215 * T) – (11.37 * v * 0.16) + (0.3965 * T * v * 0.16)
Facer Wind speed is in m/s, multiplying that with 3.6 gives you kmh.
this works for apparent temperature in metric units (round(#WCT#+0.33*#WCHN#/100*6.105*exp(17.27*#WCT#/(237.7+#WCT#))-0.7*#WND#-4)) or (round(#WCT#+0.0201465*#WCHN#*exp(17.27*#WCT#/(237.7+#WCT#))-0.7*#WND#-4))
And this one seems to work for imperial units setting (round((((#WCT#-32)*5/9)+0.0201465*#WCHN#*exp(17.27*((#WCT#-32)*5/9)/(237.7+((#WCT#-32)*5/9)))-0.7*#WND#*1.6/3.6-4)*9/5)+32)
@petruuccios Thanks - it works perfectly!
My only problem is how you got to the above from the original formula - could you please give me the original formula so that I can try and see how you got from one to the other?
Thanks again.
Do not forget to add formulas for both unit systems and alternate them using #UNITSYS# tag, if you plan on publishing it, or there will be nonsensical results.
