Can You Leave A Guitar In A Car?

If you’ve ever gone on a trip, or even just had to run errands on the way back from music lessons, you might have wondered whether you can leave your guitar in the car. 

In general, avoid leaving a guitar in a car. Temperatures above 90 Fahrenheit (32 Celsius) can damage the glue that holds a guitar’s joints together which will then reduce the overall stability of the guitar and potentially destroy the guitar. Cold temperatures aren’t much better and large shifts in temperature can warp guitars. 

Most guitars are primarily made from wood, which makes them relatively delicate instruments. Large, sudden changes in temperature and humidity can cause cracking, warping and other damage, and can even make a guitar hard to play. 

Generally speaking, an acoustic guitar, which is hollow and has thin wood making up its top, back, and sides, is more delicate than a solid-body electric guitar.

The neck is a consideration, also, and can be warped by temperature and humidity changes. That is less of a concern with modern guitars, which use truss rods to keep the neck in shape and can be adjusted if there is a problem, but it’s still something to be aware of.

Let’s take a closer look at everything you need to know and why it’s not just the heat you need to worry about when you leave your guitar in the car.

How Can Humidity Hurt A Guitar?

Another danger of leaving a guitar in a car, whether hot or cold, is a rapid change in humidity, or the amount of moisture in the air. Humidity that is too high or too low can hurt a guitar, though the damage shows up in different ways.

Humidity and temperature are different from each other, but related. As the temperature of air increases, it can hold more water, raising the humidity.

When humidity increases, that causes moisture to accumulate in the tiny pores inside the wood that makes up a guitar. That makes the wood swell. If it gets bad enough, it can push the bridge of an acoustic guitar out of alignment with the neck, making it hard to play. Especially when it comes to more advanced techniques like bending. 

If this happens, it’s fairly easy to see for yourself. Simply lay the guitar down on a flat, stable surface and sight down the neck. 

The frets and the top of the bridge should be aligned. If the bridge is higher than the frets, that could be from a wet, swollen top.

Humidity that’s too high can cause other problems, as well. It can push joints out of alignment, cause the finish to lift off, and cause a guitar to sound dull when played.

If the humidity falls too low, by contrast, the wood shrinks, which can pull joints away from each other and even cause cracks in the top, back, or sides of an acoustic guitar. These shifts can not only make your guitar sound worse but can also make it hard to play in some cases. 

Low humidity can also lead to low action and buzzing on the frets closest to the body of the guitar.

Can You Leave A Guitar In A Hot Car?

Leaving a guitar in a hot car is a bad idea, because high temperatures can cause damage that is hard, if not impossible to fix.

The temperatures inside a car’s trunk on a hot day can approach or even exceed 120 Fahrenheit (48 Celsius), far more than needed to cause irreparable damage. And this happens extremely fast. This video shows you just how this work and why a car can heat up so far: 

How Can A Hot Car Hurt A Guitar?

Extreme heat, above about 90 Fahrenheit (32 Celsius), can cause damage to the glue that holds a guitar’s joints together, affecting the structural stability. The longer the glue is exposed to that temperature, the more potential for damage.

In acoustic guitars and many hollow- and semi-hollow body electric guitars, glue is used to hold the top, back and sides together, as well as holding the neck to the body. It could also lead to the bridge and the nut getting loose.

Prolonged exposure to heat could even cause the frets in the neck of a guitar to loosen, because wood and metal react to heat in different ways and so expand and contract at different rates.

How Long Can You Leave A Guitar In A Hot Car?

Sometimes you don’t have a choice, and you have to leave a guitar in a hot car. That won’t immediately ruin it, but the longer it’s in the hot car, the more you risk damage.

Leaving a guitar in a hot car to run a quick errand is probably fine, but never leave it in a hot car for more than a few hours. If you’re traveling, for example, consider bringing the guitar inside with you when you stop for the night rather than leaving it in the car.

What To Do If A Guitar Was Left In A Hot Car?

Mistakes happen, so if you find a guitar has been left in a hot car for a long time, don’t panic. Take the guitar somewhere that’s at a comfortable temperature and leave it there until it has completely cooled down.

Don’t try to cool it off with ice or by putting it in a room with the air conditioning as cold as possible — that’s likely to cause more damage because rapid changes in temperature and humidity are really bad for guitars. 

Be patient and let it cool slowly. If you notice any problems, consider bringing it to a guitar technician or luthier to have it checked for damage.

Can You Leave A Guitar In A Cold Car?

A hot car can be devastating for a guitar, but so can a cold one. One issue is that cold air tends to be drier than hot air.

Drops in humidity are extremely dangerous for a guitar. They can cause cracks in both the finish and the wood itself and can lead to warping and twisting of the neck, as well.

The effects of the cold will harm any guitar, but they’re likely to do the most damage to acoustic guitars and hollow- or semi-hollow body electric guitars. That’s because they’re built with more places that wood meets wood, such as inside braces and where the top and sides or back and sides meet. 

Wood expands and contracts with changes in temperature and humidity, and that puts such guitars at more risk of some kind of damage from extreme temperatures and swings in humidity.

How Long Can You Leave A Guitar In A Cold Car?

Just like with heat, if you have to leave a guitar in the car while you run an errand, you don’t have to worry. But if you’re not going to be right back, you are putting your instrument at risk. 

Definitely never leave a guitar in a cold car overnight, or you could cause permanent damage.

What To Do If A Car Was Left In A Cold Car?

Just like with a guitar left in a hot car, you want to be careful when warming up a guitar that was left in a cold car, because temperature swings can be damaging.

Instead, bring the guitar into a room with a comfortable temperature and let it warm up slowly. Once it’s at room temperature you can check for damage.

What Temperatures Are Safe For A Guitar?

Goldilocks was on to something — you don’t want it to be too hot or too cold. That’s true for porridge and for where you store your guitar.

A guitar is going to be safe in temperatures where people are comfortable, generally speaking. Avoid anything colder than 32 Fahrenheit (0 Celsius) and anything warmer than 90 or 95 Fahrenheit (32 to 35 Celsius). 

The best conditions are the ones most humans like the best, as it happens: between 65 and 75 Fahrenheit (18-23 Celsius) and a humidity of between 40 and 50 percent.

How Can You Keep A Guitar At The Correct Temperature?

When choosing where to keep guitars, look at the temperature and relative humidity of the space. Any place that has a steady temperature between 65 and 75 Fahrenheit  (18-23 Celsius) and a humidity of between 40 and 50 percent is a good choice.

That means most rooms in a home will probably be fine to store a guitar, apart from places like damp basements or uncooled attics. The question becomes how to keep a guitar at the right temperature while in transport.

How Can You Transport A Guitar Safely In Your Car?

One option is to pick a hardshell guitar case. Such cases aren’t entirely airtight, but they do offer a good seal against the elements and can even out swings in temperature.

Hardshell cases can be made from wood or another material, like plastic that combines the temperature protection of a hardshell guitar case with the additional protection a humidifier offers against warping and cracking.

If you already have a case you like, another option is to use a hygrometer to keep track of the humidity some of which include both the hygrometer and a humidifier that can fit in the soundhole of an acoustic guitar.

There are less technology-dependent solutions like simple humidity control packets. 

Closing Thoughts

Even though it can be convenient, it’s not a good idea to keep your guitar in the car for any length of time. Not only can changes in temperature or humidity lead to big problems, but it’s probably not a good idea to store something as valuable as your guitar in the car either! Especially in a visible spot like the backseat thieves will be very tempted to snag your rig.