Inches of mercury or inHg is a non SI unit for pressure. It is still sometimes used for weather reports and aviation in the United States, but is considered somewhat outdated elsewhere. Pressure (symbol: p) is the force per unit area acting on a surface in a direction perpendicular to that surface. ... Composite satellite image showing the progress of a hurricane weather system approaching the East Coast of the United States Weather comprises all the various phenomena that occur in the atmosphere of a planet. ... ...

It is defined as the pressure exerted by a column of mercury of 1 inch in height at 0 °C at the standard acceleration of gravity. General Name, Symbol, Number mercury, Hg, 80 Chemical series transition metals Group, Period, Block 12, 6, d Appearance silvery white Atomic mass 200. ... Mid-19th century tool for converting between different standards of the inch An inch is an Imperial and U.S. customary unit of length. ... Height is a measurement of the distance from the bottom to the top of something which is upright. ... The degree Celsius (°C) is a unit of temperature named after the Swedish astronomer Anders Celsius (1701–1744), who first proposed a similar system in 1742. ... g (also gee, g-force or g-load) is a non-SI unit of acceleration defined as exactly 9. ...

1 inHg = 3386.389 pascals at 0 °C.

Aircraft operating at higher altitudes set their barometric altimeters to a standard pressure of 29.92 inHg or 1013.2 hPa; formerly mbar regardless of the actual sea level pressure, with inHg used in the U.S. and Canada. The resulting altimeter readings are known as flight levels. The pascal (symbol Pa) is the SI unit of pressure. ... HPA means Physiology Hypothalamic-Pituitary-Adrenal axis: The hypothalamus, pituitary and adrenal glands work together to regulate hormone levels and maintain homeostasis. ... A millibar (mbar, also mb) is 1/1000th of a bar, a unit for measurement of pressure. ... In aviation, a flight level is the nominal altitude of an aircraft referenced to a standard pressure datum, as opposed to the real altitude above mean sea level. ...