Windchill vs Heat Index vs Feel like

[Barry]

Now that I have (with help from the group) Weefx and the tempest running well I would lie to throw out a Met.

Current observation

Wind          210/3knts

Humidity    75%

Temp           20.1C

Dewpoint    15.5C

Wind Chill     20.1C

Heat Index    20.1C  

Feels Like      21.5C

From what I have read Heat index is calculated from Temperature and Humidity and Feels Like is calculated from Temperature, Humidity and Wind. with any  wind,  would it not  decrease the Feel Like below the value of the Heat Index? I am not sure how the Feel Like can be higher than the Heat Index. Are Wind Chill, Heat Index and Feels like calculated by the Tempest, weewx or a combination of both?

Barry

[Greg Troxel]

There are a number of terms, and it woudl not shock me if some equipment
used a term with a non-standard definition. The first thing you should
do is chase down what the words actually mean. Often heat index type
values are relative to 50% humidity. There's no reason to expect that
Heat Index and Feels Like have the same baseline treatment of humidity,
unless you read both definitions.

I have never seen a definition for "Feels Like". It seems to be an
acurite concept, basically heat index or wind chill, depending on
whether it is hot or cold, in some vague way. I would not be surprised
if there were a number of inconsistent definitions. I generally ignore
things like this, that aren't clearly traceable to a widely-agreed-on
definition backed up by the literature.

Weewx can use values from hardware or calculate. Read your weewx.conf
and look at the StdWXCalculate section, and read the docs about that.

https://en.wikipedia.org/wiki/Heat_index

There is also THSW, which I gather is popular in .au, but I am unclear
on it.

[p q]

Calculations are here: https://github.com/weewx/weewx/blob/6c90a174f9cf81b1b93b83b70a426199a51b47ba/bin/weewx/wxformulas.py

see the comment:

   The 'new' algorithm uses: https://www.wpc.ncep.noaa.gov/html/heatindex_equation.shtml

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Peter Quinn
(415)794-2264

[Barry]

Thanks for the comments, time to go and learn about Met and Python :-)

Barry