How To Read A Storm Glass And How Does It Work?

Storm glasses are a fun way for enthusiasts to engage with ancient weather prediction technology. It’ll sharpen up with your basic idea and skills on the forecasting phenomenon.How To Read A Storm Glass

However, these devices are controversial when it comes to accuracy. You’ll be able to predict nearly 50% of the climate changes but keep in a favorable environment.

The chemical substance inside the glass is prone to unusual reactions to radiation.

Besides, the liquid’s nature is hampered by sudden changes in temperature such as direct sunlight or freezing.

All things considered, you’ll still find it a mysterious science of the 1800s. And we’re about to walk you through some of the most common questions including how to read a storm glass, THE RIGHT WAY!

Just before we head on to that, here’s what it is in case you need some more information on that –

What Is a Weather Predicting Storm Glass?

Strom glass is a mysterious weather prediction device made with a sealed glass tube filled with (liquid) a mixture of chemicals.

Due to that, it’s also referred to as chemical weather glass. WhileRobert FitzRoy there’s no clear evidence of the inventor, it was promoted by Robert FitzRoy (meteorologist and captain of HMS Beagle) during the 1800s.

He explored in-depth how it works so that gives us a detailed idea of the correlation between weather conditions and the liquid. He also documented the prediction procedure.

Consequently, it’s also referred to as Admiral Fitzroy Storm Glass. However, in the 19th Century, Mercury Barometers replaced the use of weather globes as a more affordable option.

And with the inventions of digital technologies, weather glasses are more of a piece of surprise and conversations in the classrooms or among meteorologists.

How Does a Storm Glass Work?

How Does a Storm Glass Work

Usually, the liquid inside the glass tube is a mixture of ethanol, distilled water, ammonium chloride, camphor, and potassium nitrate. However, this composition may also vary but it’s finely balanced to mix up as a clear liquid.

And the idea behind weather glasses is that the liquid will change its state even if there’s a very minor change in the outside weather condition.

FitzRoy said, if it is left undisturbed in an ordinary environment away from direct sunlight, radiation, heat, but is well ventilated, the inner chemical will change its solubility and appear in a different form of crystallization towards the direction of the wind.

It could be just a few dots, stars, floating flakes, or father fans where each sign indicates a certain weather condition.

Although the curiosity to know about weather globes is increasing, it’s very less useful in comparison to digital weather stations. But you may still forecast nearly reliable results typically between 1 – 3 days.

In earlier times, it was said that the liquid was impacted by heat, atmospheric pressure or barometric pressure, the light, wind, and electrical change in the surrounding. Weather enthusiasts also exposed the liquid to atmospheric pressure to examine the facts.

At that time, the glass container was only sealed with a rubber cap. However, modern-day storm glasses are completely sealed to make them more precise on their way.

How to Make a Storm Glass?

How to Make a Storm Glass

Regardless of the prediction accuracy, weather glasses are very beautiful in appearance. You can easily make the perfect gift for loved ones! For the most part, you can even create your own storm glass.

Yeah…you heard it right!

Just gather a few simple chemicals and start making your own –

Things Needed to Make a Storm Glass

  • Glass tube/jar
  • Distilled water
  • Ethanol
  • Camphor
  • Potassium nitrate
  • Ammonium chloride

Step 1: Clean the Jar/Tube

Clean your storm glass jar thoroughly so it doesn’t have the presence of any unwanted chemicals. Also, make sure it’s free of dust particles otherwise the liquid will be cloudy.

Step 2: Adding Chemicals

Pour 300 ml of 50% water and 50% ethanol. Then, put 28 grams of camphor into the jar. Finally, add potassium nitrate and ammonium chloride 10 grams (each).

Step 3: Dissolving Solids

Take a pan with some water in it, warm it up, and put the storm jar into the warm water. So we’re not heating it up directly rather putting it into hot water.

With one caveat, don’t seal the jar with an airtight lid during this dissolving period. If you do, the evaporating alcohol might create pressure inside causing it to explode.

So instead you put some ice cubes on the lid loosely placing on top of the jar. Hence, the ice will distill the evaporating alcohol to keep the inner liquid at a constant pressure.

Step 4: Finishing Up

Once the dissolving process is done, take the jar out of the pan and let’s cool it down.

When the jar is ready to touch, fasten the lid firmly and safely. So there you have made it! You might want to keep the glass in an ordinary environment to cope up with the weather.

Here is the video guide to make DIY storm glass using a wine bottle.

Easy Guideline to Read a Storm Glass

Now that you know the what-and-how of storm glasses, it’s time to learn how to read storm glass and know weather conditions with it.

According to FitzRoy’s documentation on the prediction procedure, here’s the guide to predicting the weather with a storm glass –

State of Liquid

Expected Weather Condition


Clear and bright sunny day


Cloudy (Potentially with precipitation)

Small dots

Damp or foggy

Dim with small stars


Small stars on sunny winter days

Snow in about 1-2 days

Large flakes throughout the liquid

Overcast in temperate seasons, heavy air, snowy in winter

Crystals at the bottom of the tube


Threads in the upper portion of the liquid


High rising flakes

Upper air regions remain windy

High rising crystals

The colder winter it’ll be

How Accurate is Predicting Weather with Strom Glasses?

storm glass

According to a research conducted by Charles Tomlinson, “storm-glass acts as a rude kind of thermoscope, inferior, for most of the purposes of observation, to the thermometer.”

Another publication “Journal of Crystal Growth” concluded that the crystal growth and overall working procedure of storm glasses are highly impacted by the change of temperature in the surrounding environment.

It’s worth noting that the earlier weather glasses only had a typical rubber cap whereas today…they are completely sealed. Consequently, the barometric pressure may have affected the changes of the crystals. So for sealed glasses, the changes are mostly impacted by the temperature fluctuations.

From all of these studies and based on the sample results of users, we can conclude that an average of 50% accuracy can be expected.

For instance, if the crystals are indicating a rainy day but you only see overcast and threatening, it’s that much close to a reliable prediction.

Tips While Using Storm Glass

Tips While Using Storm Glass

You might already have guessed how tricky it is to predict the weather with this device!

We recommend bookmarking this article to keep the above chart as your own. So that will make the prediction a little more convenient for you.

With that in mind, here are some additional tips for using weather glasses –

  • If you see the crystals are all at the bottom and the upper portion of the liquid is very clear, the day is probably going to be clear with fine weather.
  • For upcoming rainy weather, crystals will rise gradually through the clear liquid in the form of small stars.
  • If it is to experience stormy weather with high wind, you’ll see them partly at the top. They’ll appear in the form of large leaves. Hence, the liquid will be in fermentation that’s a sign of the extraordinary change in the climate within about 24 hours.
  • When the temperature is colder particularly in winter, the crystals will show very white spots in motion and fly nearly around halfway down the top.
  • On a bright, fine, sunny day in summer, the substance will remain lower.
  • The substance/crystals will remain close to the opposite side of the bottle from which a storm is about to arrive.

People Also Ask:

1. Is storm glass liquid dangerous?

The liquid inside weather globes is usually a mixture of water, ethanol, camphor, potassium nitrate, and ammonium chloride. It would be a good practice to wear safety equipment like hand gloves because these chemicals are potentially hazardous. You won’t want to inhale the vapor that might eventually irritate the respiratory system.

2. Does a storm glass work indoors?

Indeed, storm glasses are made for using indoors having an ordinary environment away from sudden changes. Consequently, you’re not advised to place the glass near a window that receives high wind flow and sunlight. The chemical inside is highly impacted by sunlight, radiation, and heat.

Related: Ways to check room temperature with iPhone

3. Can you reset a storm glass?

Yes, you can reset it by heating up the liquid. Hence, use a pan with water that’s directly placed on the stove. Then put your weather glass in the warm water.

You may also want to shake the glass gently to mix the crystals and heat constantly. This will lead to a clear liquid that means a reset.

Final Words

Even today, these cool devices are still unknown to many enthusiasts. Although predicting weather isn’t quite in high demand because of the digital technologies that replaced all traditional methods, it can be a remarkable eighteenth-century device that can supposedly predict the weather.

Consequently, you can make it a great gift for your loved ones! You can use the results to compare with digital weather-predicting devices.

And we highly believe that this article would suffice your query exactly on how to read a storm glass, the right way!

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