How to Understand Barometric Pressure Readings

A barometer is necessary to understand barometric pressure.
••• Flickr user: markogorman

Barometric pressure is the measure of air pressure in a given area. Air pressure is the weight of air pressing down on the oceans, land and surface of the earth and is measured with a barometer. These measurements are affected by air density, which changes based on temperature, and height above the Earth's surface. By understanding changes in barometric pressure and what those changes mean, it's possible to predict changes in weather and weather patterns.

    Obtain a pressure reading using a barometer, collect the pressure reading on a weather web site or find a weather map that shows areas of high and low pressure.

    Find the exact pressure reading in millibars if possible. Millibars are the measurement of the weight of the atmosphere at a particular location. According to USA Today assistant weather editor Bob Swanson, a standard pressure at sea level is 1013.2 millibars.

    Determine whether the pressure is high or low for an area. As air rises, it cools, which according to meteorologists with USA Today, "The humidity in it begins to condense into tiny drops of water, or if it's cold enough, into tiny ice crystals. If there's enough water or ice, rain or snow begin to fall." Low pressure is associated with bad weather and high pressure with fair weather.

    Note the wind speed, as this can also be affected by pressure changes because air moves from high to low pressure areas.

    Document the changes in pressure over time and the weather outside and you will be able to more clearly understand how pressure changes can affect and correspond to weather.

    Tips

    • Barometric pressure on a mercury barometer is measured in inches of mercury. On average, sea level pressure supports about 30 inches of mercury.

Related Articles

Barometer Facts for Kids
How to Look up Past Weather History by Dates
How to Find a Z Score
How to Convert mm Hg to in Hg
The Definitions of Temperature, Dew Point and Barometric...
How to Convert Barometric Pressure to mmHg
How to Find The Slope of a Line Given Two Points
How to Convert hPa to Altitude
How to Read Weather Radar
What Is the Humidity of the Mojave Desert?
How to Find Barometric Pressure in My Area
What Happens When Barometric Pressure Rises?
How to Read a Water Barometer
How to Read a Digital Barometer
How to Calculate the Mean Annual Temperature
How to Calculate Statistical Mean
How to Recalibrate a Springfield Barometer
How to Find the Area & Width of a Rectangle
Barometric Pressure & Snowstorms
The Average Daily Wind Speed
How to Calculate Relative Accuracy