Your smartphone already does an amazing variety of stuff. It’s your camera, navigation guide, compass, it can even serve as an impromptu level so all your pictures hang straight. You may not know that it can also function as a barometer or altimeter, too.

How Barometers Work

Many of us have that amateur meteorologist inside of us, so while we can always pull up the weather forecast using an app or a website, it’s a lot more fun to track atmospheric pressure trends on your own using a barometer.

Barometers measure air pressure. There are several kinds of barometers. Torricellian and aneroid are the traditional mechanical barometers you might have seen in the past, and there are the digital barometers as found in your smartphone and high-end outdoorsy watches.

If you use a smartphone, it probably already has a built-in barometer. Phone manufacturers include barometers to improve GPS elevation results, because they can be adversely affected by atmospheric pressure. While you may never have any need or desire to know your current altitude or atmospheric pressure, aspiring meteorologists, hikers, or simply curious folks might really like to know.

Barometers measure atmospheric pressure, so you can get a general sense of what’s going to happen by whether a barometer rises or falls. If the barometer goes up, then that means the weather is going to be fair. If it goes down, then it’s probably going to rain, snow, or indicate some other type of inclement weather.

Today we’ll show you the basics of how to use a barometer app on a smartphone. You can find and download barometer apps for both iPhone and Android, which you can use to do your own weather predictions.

Using Your Smartphone Barometer

On your smartphone, you can use a barometer to get an idea of how the weather is trending.

For example, when we use the Barometer and Altimeter app on our iPhone (you can use whatever one you prefer however, they all function in pretty much the same way), we tap “Set” to calibrate the red needle so it lines up with the black one.

As time passes, the black needle will move, either up or down, which will indicate how your local weather is trending. In the following screenshot, we see that the needle has moved up, which means the weather will be fair. If it were to move down, then we would probably need to bring an umbrella!

Using the simply-titled Barometer app on Android, we calibrate the needle to zero so we know how it moves over time.

In addition to being able to predict the weather, you can check your current altitude. It’s important here to keep in mind the difference between altitude and elevation. Elevation is the height at which the land mass you’re standing upon extends above sea level. Altitude is how high you are above that land mass.

So, while your phone might be able to tell you how high you are, such as in a plane or when climbing a hill, if you don’t already know your elevation, it won’t tell you how far you are above sea level.

Know also, barometric pressure is going to differ with your current weather and position, therefore you will have to set the reference altitude and pressure to get an accurate reading.

Your barometric pressure needs to be set to your local pressure in order for the altitude reading to be correct. If your atmospheric pressure changes, so too will your altitude even if you don’t move or change position.

Similarly, the relative altitude value needs to be set to your current local altitude for the atmospheric pressure to read correctly. If you don’t change altitudes, the barometric reading will remain accurate. In order to obtain your station pressure, you can set the reference altitude to zero.

Using the Android app, you can view altitude reading right on the barometer’s face.

And obviously you can calibrate both sensors just as you can on the iPhone equivalent.

Basically, the idea here is to get a small reading (zero or one) on the altimeter so that as you change positions and elevations, you will know how high or low you are.

RELATED: How to Use Your iPhone as an Impromptu Level

Most people like to get altitude readings for when they’re hiking, or simply out of curiosity, such as when going from place to place. The barometric pressure reading on the other hand, will typically appeal to anyone into DIY weather-forecasting.

There are quite a few barometer apps available through iTunes and Android Play, so if you do a simple search for the keyword “barometer” you can easily find one that suits you.

Profile Photo for Matt Klein Matt Klein
Matt Klein has nearly two decades of technical writing experience. He's covered Windows, Android, macOS, Microsoft Office, and everything in between. He's even written a book, The How-To Geek Guide to Windows 8.
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