average range of barometric pressure
Average Sea-Level pressure: 101.325 kPa /1013.25 mbar / 760 mmHg / 29.921 inHg. Pressures seldom increase or decrease 1 inch of mercury (3.386 kPa /33.86 mbar / 25 mmHg) above or below the 30 inch mark (101.591kPa / 1015.91 mbar / 762 mmHg) unless weather conditions are extreme.