Toybox.Weather.CurrentConditions.pressure clarification

Hello Garmin??? 

From a pilot (not Garmin)…  

Short answer: Neither.  It tells you how far from standard atmosphere you are.

Longer answer:  It tells you how far from standard sea level you are by measuring the difference in the weight of the atmosphere on a standard day at sea level and the weight of the atmosphere of where you are.  It’s an adjustment amount to tell someone how much more or less pressure the atmosphere is applying to a location compared to standard. I can’t pick a gooder way to say that right now.

Pilots adjust the aircraft’s altimeters from standard (29.92 in the US, 1019 most international places…and Garmin) so that we accurately measure where the ground is.  For example, where I live the airport elevation is 856 feet.  In order for that altitude to show on my altimeter right now, I need to dial in 29.56 inHG into the altimeter.  If I didn’t make this adjustment and left the altimeter in standard, and I was flying without visual reference to the ground, I’d impact the ground while my altimeter was still indicating 1,216 feet (note: early morning math may be off a few feet).  The lower pressure makes the altimeter feel higher than what it actually is.

(insert your favorite “One pilot says to the other pilot, 'What’s that goat doing in these clouds?'” joke here)

Clear as mud?  Basic, but I hope this answers your question.

Thanks, clear as mud.  I'm looking for more solid info on what this is from Garmin.  Especially since there are so many places where the API documentation is just plain wrong or misleading.  

Can't you decide it by looking at the data you get and the data from the same weather station in another place?

...tested with my EDGE device:

Now... clear as water?

PS: Gumpoldskirchen is at 250 m above sea level.
The difference between local and sea level pressure is about 1 hPa per 8 m.

101586Pa ~= 1016hPa so it seems the Weather is at sea level?
But also ActivityInfo almost matches: 98495Pa ~= 984hPa, and 989hPa is only 5 Pa higher, which means it's about 40m lower?
But where is the 250m? that should be ~31hPa difference (BTW IMHO there's a typo: is it really 1hPa/8m or it's 1Pa/8m?)

250 m above sea level is the official altitude of Gumpoldskirchen. It is a hilly area near where I live. I don't know the exact altitude of the weather station in Gumpoldskirchen.

I live at 235 m above sea level - and this is where I took my Edge measurements.

(...and I'm sure none of this is mathematically accurate)

flocsy🤠 said:

BTW IMHO there's a typo: is it really 1hPa/8m or it's 1Pa/8m?

From internet: (It seems to be ok… but is only valid for elevations below 500 m)
Da der Luftdruck mit zunehmender Höhe abnimmt, musst du den relativen Luftdruck für jede 8 Meter Höhe um 1 hPa erhöhen. 

English: As the air pressure decreases with increasing altitude, you must increase the relative air pressure by 1 hPa for every 8 meters of altitude.

985 hPa local plus 31 hPa from elevation (250/8) —> 1,016 hPa

…ok, these hPa figures are taken from my Edge, and I live at 235 + 6 m for 2nd floor = 241 m, and 241/8 makes only 30 hPa difference instead of 31…  

Generally, in a weather report, the pressure is MSL, and if you are close to the weather station but at a different elevation, the pressure you observe will be different.  In fact, if you are stating next to the weather station, what you observe can be different than what's reported for that weather station, due to it's elevation.

With my own weather station, one of the things you configure is the WS elevation, so when it displays pressure, it's adjusted to MSL. 

Other things come into play with garmin weather, such as how old a reading is.  For me and Garmin, the reading is always 51 minutes after the hour and sometimes a reading is missed so the value can be up to 2 hours old, where a storm rolled through and it's clear again, but I can see that on my own weather station that updates every few minutes.

Out of the 3 different sources of weather I use with CIQ, the most accurate is Weather Underground, where the data is right where I live.  OWM isn't bad, as it's from a ranch not far away, and the worst is Garmin, where even the temperature with Garmin can be off by 10F.  It's probably better in the flat lands of Kansas,