What Is Barometric Pressure? How can I use it to predict the weather?

What is Barometric Pressure?

This is the measure of pressure changes in the weather, think of it as the weight of the air. These changes tell us what is happening with the weather, and is used to predict changes in weather patterns. If the air pressure changes, this is usually an indicator that the weather is changing.

A rise in pressure usually indicates good weather is coming, and a drop usually indicates bad weather is on it's way. This can vary depending on your altitude and the level of moisture in the air.

How does it work?

Now time to get a little technical...Due to the gravity earth is surrounded by a mantle of air, this is known as the atmosphere. The static pressure that acts to the surface of the earth is called atmospheric pressure.

Because of variable warming of the different latitudes, formation of the continents and seas, and motion processes in the atmosphere, the atmospheric pressure is uneven.

The global mean value of the atmospheric pressure at sea level is 1013.25 hPa. In Central Europe it varies mainly between 990 and 1040 hPa. You can set up your barometer to read at the appropriate settings.

How do you measure Barometric Pressure?

This measurement can be expressed in millibars(mb) or in inches or millimeters of mercury (Hg).

How do I measure the barometric pressure at home?

First you need a barometer, when your barometer first arrives you need to sync it to your local area. You can go this by googling the barometric pressure and your location the day you are setting it up (we have a great infographic on how to do this here). This will make sure your barometer (or weather station which contains a barometer) matches your local weather. Once it is set up you will not have to do this again, as it will measure the changes in barometric pressure for you.

You can use the pointer to set a base line for weather changes on any given day. The you will know if the measurement has moved or not during the day.

As the barometric pressure changes the metal arm will move on your barometer to give you a reading. Most barometers are labelled with words or symbols that indicate if the change is towards good weather, or bad weather.