Barometric pressure of under 29.50 inches of mercury at sea level is considered low. At sea level, a normal barometer reading is between about 29.70 inches of mercury and 30.20 inches. More » Science Earth Science Atmosphere

An area is considered to have high barometric pressure when it has greater atmospheric pressure than the surrounding area. Normal barometric pressure is between 980 millibars and 1,050 millibars. High pressure systems ar... More »

Normal barometric pressure is typically around 101.325 kPa / 1013.25 mbar / 760 mmHg / 29/921 inHg. Pressure rarely increases or decreases more than 1 inch of mercury (3.386 kPa / 33.86 mbar / 25mmHg) above or below the ... More »

Barometric pressure was discovered in about 1644 when physicist and inventor Evangelista Torricelli invented the first mercury barometer. Torricelli was an assistant to Galileo Galilei who suggested that Torricelli try u... More » History Inventions

The normal air pressure at sea level is 14.7 pounds per square inch. Standard atmospheric pressure can also be expressed using different units, including 1013.25 millibars, 1013.25 hectoPascals, 760 millimeters of mercur... More »

Air pressure, the force exerted on a mass by the weight of air particles, is measured in either inches of mercury or in millibars, represented by inHg and mb, respectively. One standard atmosphere, represented by the sym... More »

Low barometric pressure is caused by warm air from the planet's surface rising, decreasing the amount of air pulled downward by Earth's gravity. This rising heat can lead to adverse weather conditions. More »