There is a need to adjust this sensor for height. I found for every 100 feet the pressure will be down 35 millimeters. It seems no one uses these readings. So if you do the math and adjust the digital barometric reading for height it matches the atmospheric pressure. I did some research and found that digital barometers tend to show lower readings than mercury barometers, it’s because digital barometers measure **absolute pressure** while mercury barometers measure **atmospheric pressure** ². Absolute pressure is the sum of atmospheric pressure and the pressure exerted by the weight of the air above the barometer ². Since digital barometers measure absolute pressure, they tend to show lower readings than mercury barometers, which measure atmospheric pressure only

You can search the forums here. I posted the formula to translate readings. Once done, I see very little difference to the values my favorite internet weather service shows me for my location.

Thank you. I found the formulas and made the adjustments.