WRAL WeatherCenter Blog

I am setting the atmospheric pressure for an instrument that has as its units inHG. i was wondering if barometric pressure is the same thing as atmospheric pressure and if the readings that are given on your website (typically around 29) for barometric pressure are in those units or something else alltogether. I appreciate any help you can give me.

Posted January 21, 2008 8:57 a.m. EST

MIKE MOSS SAYS:      Steve,    You are correct that barometric pressure is often given in units of inches of mercury (Hg) and that your barometer can be set using readings for about the same time period from our web site or from others reporting the value from a nearby weather observing site. Other units that are frequently used to report air pressure are millimeters of mercury, millibars, hectopascals, and pounds per square inch. The average sea level pressure in our atmosphere, for example, is 29.92 inches HG = 716 mm Hg = 1013.25 mb = 101.3 HPa = 14.7 psi.