How to Calculate Barometric Pressure From Temperature

A common problem in meteorology and atmospheric studies involves how to calculate barometric pressure from temperature. According to Hans Peter Schmid at the University of Indiana, the gas laws in physics offer a solution to determining barometric pressure at a given altitude given a baseline pressure of one atmosphere (equivalent to atmospheric pressure at ground level) and a constant temperature. Carl Nave at Georgia State University points out that the barometric formula provides a simple approximation of this relationship, although it slightly overestimates barometric pressure at higher altitudes due to the tendency of temperature to decrease as altitude increases. However, as a rough baseline the barometric formula and the gas laws allow for the calculation of barometric pressure to be made from temperature.

Things You'll Need

  • Thermometer
  • Notebook
  • Barometric formula calculator online
  • Standard atmospheric pressure value
Show More

Instructions

    • 1
      A simple thermometer can help determine barometric pressure.

      Place the thermometer in an outdoor location and wait for the mercury reading to stabilize.

    • 2

      Record the temperature in the notebook using the Celsius scale. Celsius is used because it is easier to convert to Kelvin.

    • 3

      Enter the value of 101.3 in the white box next to the kPA text on the Barometric Formula calculator. KPA stands for kiloPascals, and is the standard measurement for atmospheric pressure--101.3 kPA equates to one unit of atmospheric pressure, calculated at sea level, and is the baseline for the barometric calculation at varying heights.

    • 4

      Enter the temperature value from the notebook in the second white box under the uniform temperature section. This box corresponds to degrees Celsius and will automatically convert to the Kelvin scale.

    • 5

      Type the desired height in either feet or meters under the section beginning with the text "then the pressure at an altitude of."

    • 6

      Examine the three white boxes immediately below the height entry on the calculator. These will display the barometric pressure at the given temperature and altitude in several units, and the third box gives the pressure value in kPa. This can be compared to the baseline atmospheric pressure to determine the pressure differential between the Earth's surface and the given altitude.