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What is Atmospheric Pressure?

Weather map - atmospheric pressure
By AcuRite Team
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What is Atmospheric Pressure?

What is Atmospheric Pressure?

Atmospheric pressure is also called barometric pressure because barometers are used to measure it. Atmospheric pressure, barometric pressure, and air pressure all refer to the same thing: the weight of the atmosphere at any location, generated by the downward force of gravity. Pressure decreases with increasing elevation because there is less air above you.

Surface air pressure equals weight of air in column above unit area

What is Air Pressure?

Air pressure is commonly used when talking about tire pressure as it is the pressure of the air around us. Air pressure might be commonly used in place of atmospheric pressure but is less specific because it is not defined by the force of gravity. Use a tire gauge when measuring the air pressure in your tires, use a barometer when measuring atmospheric pressure or barometric pressure to understand changing weather patterns.

How Is It Measured?

Electronic pressure sensors used in AcuRite products and most home weather stations measure pressure changes through device that includes a quartz membrane secured over an evacuated chamber. As this flexes with changes in pressure, it measures the strain due to an applied force over an area. The output of voltage fluctuations are then converted to digital to be used on home weather displays or your online apps and weather dashboards.

My AcuRite screenshot with callout for pressure reading

The Effects of Atmospheric Pressure

Atmospheric pressure changes occur with large-scale high and low pressure systems moving across the Earth. High pressure generally implies clear skies and uneventful weather while low pressure generally implies clouds, precipitation, and active weather. Most home weather stations can help you understand what weather is on the way by tracking the pressure trend. In addition to knowing about approaching weather, monitoring pressure changes at home can help you understand your joint pain and headaches or migraines. Even your hunting and fishing trips can be affected by changes in pressure!

One pressure measurement alone doesn't help meteorologists understand the weather, but if we have multiple readings of increasing or decreasing pressure values, then we can have some idea of the forecast. Increasing pressure tells us higher pressure is coming and skies will clear up, while decreasing pressure signals a low pressure system is on its way bringing clouds and possibly rain.

United States weather map showing areas of high and low pressure an resulting weather patterns

The warm and cold fronts accompanying these high and low pressure systems are what trigger rain and severe weather events. You may recognize this image from the National Weather Service, similar to weather maps often shown by your local TV meteorologist. You will see precipitation along and ahead of the fronts associated with low pressure, while generally uneventful weather accompanies high pressure systems.

February 5, 2018
Gary Meyer
February 13, 2018 at 10:57 AM
How do I get my station to show the right pressure?
February 14, 2018 at 5:31 PM
Are you looking for help on how to change your pressure reading from station pressure to adjusted pressure? For help with your specific station or display, feel free to call our Support Team at 1-262-729-4850 M-F 7am to 5pm Central Time.
Jason Moore
May 12, 2018 at 5:07 PM
My 5-in-1 sensor displays the correct atmospheric pressure on the color display it came with, but my smartphone and Windows 10 computer connecting through the Access device I bought to replace my old AcuRite Hub, read consistently 8-12 inches Hg lower. When I first got the Access device, the readings were the same (or at least close) on all displays, then suddenly a few weeks ago the Access provided ones started reading 8-12 inHg lower. Interestingly, the sensors in my Samsung Galaxy S8+ smartphone display the same low pressure readings. I use the NWS readings at our local airport (about three miles away and some 400 feet lower) for reference to verify the readings, and the color display that came with the 5-in-1 is always very close.
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