Barometer issue

I have exactly the same issue. I think, there is quite big number of wrongly calibrated F5x watches (many users complain). Would be not a big deal if we got an option to make the calibration on our own. But it is not possible, at least not for current firmware. I don't understand why?!

However, the altitude measurements are based on the relative atmospheric pressure changes, so you can have correct vertical profile even if the barometer is uncalibrated, i.e. with the wrong mean sea level pressure.
You can calibrate only the height.

I have reported many time to beta team this issue and I ask them why we can't calibrate barometer too...

Good morning. RMA watch (reason: screen flickering). Same issue. 11mb high. My first wath was absolutly accurate with the barometer. Both watches compared with my wheather station.

Calibration

There´s a simple way to calibrate it. In an open space, select altimeter, and select calibrate using GPS. Once it is calibrated, the pressure change. If you know your exact heigh, you can put it directly and it is enough.

There´s a simple way to calibrate it. In an open space, select altimeter, and select calibrate using GPS. Once it is calibrated, the pressure change. If you know your exact heigh, you can put it directly and it is enough.

Certainly not, mean sea level pressure (shown by watch) is atmospheric pressure reduced to the sea level, i.e. 0 m. To have correct barometric values you have to calibrate absolute atmospheric pressure, not the reduced one which is a function of altitude and temperature (the idea is to have comparable MSLP for different geographical places at different heights). The procedure you are talking about is there just to set correct elevation, not to calibrate barometer.

Clear

Certainly not, mean sea level pressure (shown by watch) is atmospheric pressure reduced to the sea level, i.e. 0 m. To have correct barometric values you have to calibrate absolute atmospheric pressure, not the reduced one which is a function of altitude and temperature (the idea is to have comparable MSLP for different geographical places at different heights). The procedure you are talking about is there just to set correct elevation, not to calibrate barometer.

Clear information. Thanks. In my Fenix 5, once I goes to the swimming pool, it change the height and pressure and I have to calibrate the height manually.

Clear information. Thanks. In my Fenix 5, once I goes to the swimming pool, it change the height and pressure and I have to calibrate the height manually.

Yes, it is necessity to calibrate the altitude once the weather is changed because it is determined by the changes in atmospheric pressure. Even if the watch is quite sophisticated so it can detect whether the pressure drops/rises due to your movement up/down (in this case your altitude is changed) or whether the pressure changes due to weather, it is still needed to correct your altitude from time to time. Unfortunately, the absolute barometric pressure can't be calibrated and hence the MSLP shown by watch (if you have one of those wrongly calibrated) is not consistent with the meteorological situation. (Try to imagine, that the thermometer shows the current temperature with the 10 deg.C offset, a bit annoying.)

Same issue. Mine is consistently 10mb higher than local NWS observations, a cheap home baro and a Fenix 3, which are all within about 2 mb of each other.

Garmin Support says this "appears to be expected behavior." It is a disappointing response considering the F3's relative accuracy.

Yes, it is necessity to calibrate the altitude once the weather is changed because it is determined by the changes in atmospheric pressure. Even if the watch is quite sophisticated so it can detect whether the pressure drops/rises due to your movement up/down (in this case your altitude is changed) or whether the pressure changes due to weather, it is still needed to correct your altitude from time to time. Unfortunately, the absolute barometric pressure can't be calibrated and hence the MSLP shown by watch (if you have one of those wrongly calibrated) is not consistent with the meteorological situation. (Try to imagine, that the thermometer shows the current temperature with the 10 deg.C offset, a bit annoying.)

Within an activity, you can have the watch display both the ambient pressure and the pressure at MSL, both as data fields. Outside of an activity when you look at the barometric history graph it only displays the MSLP. That's because the history is useful for trending, for predicting weather changes in the backcountry; if the chart jumped around every time your location changed, you wouldn't be able to recognize the trend. (It's good that the watch behaves like this.)

When you calibrate to a known altitude, the watch also updates the MSLP, it just doesn't immediately show you this. But you can verify if you want to.

Unfortunately I don't have a great picture to illustrate what I'm talking about. Here's an analogy. You can set up data fields for barometric elevation and GPS elevation and display both side by side, just like you can with ambient and sea level adjusted pressure.