This website is reader-supported. When you buy through links on our site, we may earn a small affiliate commission.

How to use a barometer

Last Updated: 09.12.21

You can find out the weather forecast by checking your phone or turning on the TV or your car radio. Back in the day, it really didn’t use to be as simple as that. People had to use special devices to find out what their skies would bring in the future.

One of these particular tools was the barometer, so keep reading to find out what are the most important features you should look for. Despite having been replaced over time, especially as its design has evolved much like that of many other gadgets, a barometer is still a charming device to have around. Moreover, it is commonly utilized in meteorological circles, but if you want to learn how to read one, we can be of some assistance together with some helpful tips on how to calibrate it. So don’t worry, it’s not as difficult as it seems and once you’ll get the hang of it you might also want to acquire and calibrate an autoclave sterilizer similar to what we described in this informative post.

What type of barometer do you have?

These devices aren’t all the same, and that’s because they differ largely when it comes to their construction and even their capabilities. The mercury barometer was the first ever to have been invented, and it boasted a mercury cistern and a closed tube of about thirty inches in height. The level of mercury was either raised or lowered depending on the air pressure.

This kind of barometer is no longer available to purchase, and that’s because mercury is a highly dangerous substance for humans and other living beings. It is no longer utilized in thermometers, either, so that should give us a pointer as to whether or not we should be avoiding it.

However, if you’re resolute on getting one or maybe you are a collector, you can find vintage models available online. Keep in mind that a mercury barometer is far less accurate than a modern alternative.

The aneroid barometer was invented in the first half of the 19th century and was commonly utilized on ships and in old weather stations. Unlike its Mercury counterpart, this design didn’t have any liquids. In fact, it relied on a small box made of an alloy of copper and beryllium which either expanded or contracted depending on the chances in air pressure.

Finally, electronic barometers are those utilized nowadays and are by far some of the most accurate ones. They are typically outfitted with a thin wire that changes its electrical resistance in accordance with the atmospheric pressure that acts on a diaphragm wrapped around that wire.

It goes without saying that utilizing older models of barometers is way harder compared to using modern devices. But as you’ve probably figured out by now, some people like a challenge whereas others just want to know the weather forecast as quickly and easily as possible. For the latter, there are things called portable or home weather stations that they can install and use both conveniently and efficiently. For the former, however, there are the somewhat traditional models that we have mentioned earlier on.

Forecasting the weather with the help of an aneroid barometer

We chose to leave out mercury barometers from this article because they are dangerous and as such, we do not recommend them even for collectors. Unless you know for sure that you are not going to use the device and that you can store it safely and away from other people, try to avoid purchasing such a product in the first place.

You can set up an aneroid barometer with ease. All of the equipment that you are going to utilize consists of a small screwdriver. You have to first calibrate it, which means that you should get the right barometric pressure as per the area you live in from some resource. Some people like using online weather forecast websites to match the barometric pressure of the barometer to that of their location.

A typical aneroid barometer is outfitted with two hands. One of them shows the actual pressure reading, and the other has to be adjusted manually when you take a measurement and align it with the pressure reading. Unfortunately, using an aneroid barometer calls for a bit of effort and commitment, which means that you will have to pay attention to the orientation of the needle and check on the device every few hours or so.

While some might argue that the manual needle is virtually useless, the fact is that it can offer a lot of information as to the direction that the automatic needle has moved in and just how far.


Forecasting the weather with a digital barometer

You can come across a plethora of great barometers for sale these days, and most of them are electronic. What’s more, you might come to notice that most such devices have incorporated other features to as to be as convenient as possible. Some can tell you the outdoor and indoor temperature, the moon phase, the time, and the weather forecast for the coming days.

As such, using a digital barometer is far easier compared to setting up and employing an aneroid barometer. Nevertheless, a digital weather station doesn’t look that good in a somewhat traditional setting or interior design, and it’s definitely not designed for people who like to tinker and study things in detail.

With a digital barometer, all you have to do is go through the manufacturing brand’s instruction manual when you take it out of the box. The device is responsible for anything else, and let’s face it. That takes some of the charm out of the whole experience.

Use any resource you can get

If this article hasn’t helped you all that much when it comes to explaining to you how a barometer can be used, we suggest going online and doing a bit of research. For traditional models, there are sites like The Art of Manliness and even wikiHow that have published extensive articles on how you can set and observe a barometer as best as possible.

There are even several YouTube videos that can give you a hand with understanding barometer readings. So, as you can see, you needn’t go to extreme lengths to learn how to utilize such a device. Besides, with a digital one, using it is a piece of cake.


About air pressure and how the weather is tightly linked to its changes

To understand the science behind a barometer, you need to learn more about air pressure and its tight connection to the changes it determines in the weather. While we have today all sorts of fancy equipment to predict the weather, centuries ago people had very few methods and devices to do so. One of them was the trustworthy barometer, for reasons that will be explained right away.

This type of pressure is called barometric pressure, and it is used to calculate the weight of the air that is experienced at ground level. The weight of the atmosphere around us makes us experience specific effects on the body; for instance, it is well known that low pressure is associated with pain, and, in particular, headaches.

What happens is that a lower air pressure pushes against our bodies, and that creates a condition for tissues to expand. That causes your joints to hurt and your head to feel aches. Atmospheric pressure is measured in inches of mercury, still, and that’s a reminiscence of the older barometers that were used centuries ago. It was Torricelli’s barometer that first used mercury for calculating atmospheric pressure, hence the measurement unit.

Now, let’s see the connection between how much the air around us weighs and weather as we all experience it. Any weather map can show you areas with low pressure and high pressure. When they collide, changes in weather occur, and that’s how meteorologists predict the weather. Areas of different pressure that meet will cause the air to rise.

While it rises, it begins to cool, and that’s when the particles will transform into water, hence into rain or snow, depending on the temperature in the respective area. While this is not, by far, an extensive explanation, it should help you understand how air pressure works and its connection with the weather.


The importance of understanding air pressure and its influence on the weather

Before getting to learn more about modern barometers and how they work, we should focus a little on the behavior of the masses of air and the role they play in how the weather around us changes. We are surrounded by the atmosphere, and not only at ground level, but also up in the clouds. The way the temperature of the air above the earth behaves plays a significant role in weather changes.

Also, the planet Earth and its particularities influence the changes in the atmosphere. For instance, a large mass of air that travels over large surfaces of continental landmass will not be the same as what happens with those that travel above large surfaces of water, such as oceans. When there is a difference between these masses of air, winds start, and then the pressure suffers changes, as well.

Meteorologists call these patterns pressure systems, and they are an essential tool for analyzing weather conditions and how they change. They don’t remain the same as the masses of atmosphere of different temperatures collide; they suffer changes as they travel over land masses and oceans.

An important discovery regarding the pressure of atmosphere was made during the 17th century, when Blaise Pascal, a scientist, and philosopher, realized that its value would decrease with height. He was the first to understand that even the pressure calculated at ground level could be used to understand critical weather changes. It is because of such discoveries that today, meteorologists can predict whether a storm will head over to your area, or if, instead, you will have fair weather.

The atmosphere that gets cooler when it is on the rise is responsible for the formation of precipitations. The clouds that we see up in the sky are a result of this phenomenon. For that reason, the study of weather changes is quite a fascinating topic, and even people who are not qualified meteorologists are interested in learning more about it.

The digital barometers of our age

We already talked about the older types of barometers in this article, so we should now focus on digital barometers and how they can help us determine weather changes and what conditions we should expect. Of course, if we want to know about what we should expect when we go outside, whether we should prepare for rain or we should leave our warm clothes at home, we only need to turn on the TV or use an app on our smartphones.

Still, some people like the idea of being able to read details about atmospheric pressure while using a device that can be installed in their backyards. Weather stations for home use are now available, and they do include digital barometers in the array of tools they use to offer you an accurate prediction of the weather changes happening outside while you sit comfortably inside your home.

These new and improved barometers come equipped with sensitive cells that respond to the changes that occur in atmospheric pressure. They no longer use mercury, like old models, but they are highly accurate, and they are an integral part of any weather station device. A sophisticated weather station will give you information on more than just barometric pressure, and you will also learn about temperature changes, possible precipitations, wind speed, humidity, and so on.

Now, to see how you can get a barometric reading on your digital model, we need to look at the mechanisms used so that it can predict the changes in barometric pressure. Digital models have something called a detection cell that measures air temperature. Its role is to relay electricity, and that’s influenced by changes in atmospheric pressure.

When this value changes, the strength of the electricity that flows through the detection cell modifies, as well. This way, you will get an accurate measurement of air pressure. An interesting fact you should know about these detection cells is that they are very small, which is why it is possible for manufacturers to integrate them into various devices. That’s why weather stations use them, and you can even have one inside your smartphone.


How to make sure that your digital barometer gives accurate readings

There are a few things you should know when you decide to place your weather station – and the barometer inside it – in your backyard. Several rules should be obeyed. First of all, you should put it in an area with enough shade. If the sun were to cast its rays directly on the weather station, you wouldn’t get proper readings because the sensors will register a higher temperature than it actually is.

Also, you need to make sure that the sensors are not close to heat sources. Even more, the place for your weather station shouldn’t be in an area with plenty of wind or drafts. Last but not least, make sure to place the device on a flat surface where it can’t be knocked over too quickly.


What do all those numbers say?

By far more comfortable to use than a traditional barometer, a digital model offers you the ability to read the barometric pressure and get a feel of what the weather will be like. It doesn’t take a lot of learning to know how to interpret this type of barometer. What you need to know, for starters, is that when the air pressure rises, there are better chances of fair weather, and when it drops, you are more likely to encounter stormy weather.

But, of course, you might be interested in gaining a little more knowledge about barometric reading and what it is all about. Here are some guidelines to help you understand how your barometer works and, also, to ensure that you know precisely what the device you use can tell you about upcoming weather.

When the pressure is under 29.80 inHg, but it is on the rise, that means that you will see dry and cold weather. If it drops slowly, you can expect some rain, and if the dropping rate is fast, you can even see snow.

The next interval, you should be aware of is between 29.80 inHg and 30.20 inHg. If your barometer shows such values, you will understand whether the conditions will remain the same or they will change. If you notice a steady air pressure or that it rises, it means that the weather will stay the same. In case it drops, there will be some changes, but nothing too severe. Still, if you notice a sudden drop, that’s a sign of precipitation.

When the value shown is above 30.20 inHg, there are certain weather conditions that will occur. Again, if the pressure is steady or it rises, you can expect fair weather that will remain like that for some time. A slow drop is also a sign of pleasant weather conditions, while a sudden drop let you know that the weather will be cloudy, although still warm.

You might have noticed that there is also a correlation between air pressure and temperature. The two are connected for forecasting the weather, and warmer temperatures are associated with high pressure, while cooler temperatures with a lower pressure, hence also the chance of precipitation.


What measurement units are used for calculating pressure?

From this informative article, you must have understood by now that mercury is no longer used for modern barometers and weather stations that can be used at home or in your backyard. However, the way the pressure is calculated, and its values are presented might make you believe that the dangerous chemical is still widely spread, which is not precisely the case.

Now, to explain this aspect a bit better, let’s understand what the term ‘one atmosphere’ means. The average, or ordinary barometric pressure, used to be expressed by this term. It is the equivalent of 760mm of mercury; this was written as 760mmHg, with Hg being the chemical symbol of mercury. That was not the only traditional way of explaining the value of pressure in the measuring devices.

Another common measuring unit was Torr. This was inspired by the name of the father of the barometer, Torricelli. Its value was equal to 1mmHg, so such values can be used interchangeably, without significant errors. If you are interested in another archaic term, that would be the millibar; 1 Torr was 1.33 millibars, to give you an idea about what scientists used centuries ago.

Also, 1 Torr was the equivalent of 0.0013 atmospheres. The modern unit used today is Pascal, inspired by the French scientist mentioned earlier. Today, one atmosphere – which is the regular pressure – is the equivalent of 101,325 Pa. To make things simpler, today’s scientists also use kilopascals; so the same value of one atmosphere can also be expressed as 101.325 kPa.


Can you predict the weather from your own backyard?

We are surrounded by technology today, and quite an essential part of it is used to provide you with a weather service that everyone can understand. The science of meteorology has evolved tremendously, to such a degree that people know in advance if there is a hurricane coming their way. Such scientific advancements are very useful, and they would have never been possible without the assiduous study of the pressure of the atmosphere, and how air masses can influence the weather around us.

This article on barometers showed you the various type of devices that have been used through the ages, and a little bit of history, along with the critical discoveries made by scientists from different eras. You’ve also learned about the various measurement units used in the past, and how to interpret the values that show the changes in pressure.

Modern-day weather stations come in all shapes and sizes, and some are even intended for home use. They include a barometer, too, besides other sensors such as those that calculate the humidity levels, the wind speed, and so on. In other words, if you use the right tools, yes, you can forecast weather changes that are particular for your area, and that without having to rely on the information provided by meteorologists on TV.



Ioana Moldovan

Ioana’s professional experience in the optics field has helped her understand the value of passing her knowledge forward. Her curious personality helps her gather useful information for her readers and her goal is to make technical information fun and accessible to everyone.

Notify of
Inline Feedbacks
View all comments Protection Status