Should I Worry About Ukulele Humidity?

10 May 2015

Should I Worry About Ukulele Humidity?

OK, something that kind of gets my goat this one, and in danger of descending into a famous Got A Ukulele rant... Do you need to worry about ukulele humidity?

Why only a  potential rant Baz? Well, I realise that we live on a BIG planet and for many people, humidity is indeed a BIG problem with solid wood instruments. I suppose what started to get the hackles up with me was when I see people in the UK or other temperate climates worrying about humidity and, worse, still, spending money on gadgets to solve a problem that some bright spark convinced them was really needed. Not only can it be that case that in many cases such gadgets are completely unnecessary, but they can also cause as much damage the other way.

OK, back to basics. Humidity, or to be more precise 'relative humidity' is a measure of how much moisture there is in the air. The term 'relative' is an important one as humidity is measured as a percentage and it is not a measure of liquidity. A high humidity is something like 60 plus percent, but that doesn't mean the air is 40% away from being total water. That would be ridiculous (but if the science interests you, relative humidity is to do with the ratio of the  pressure of water vapour to that of water....)  . So anyway, I will cut to the chase and a 'good' relative humidity for musical instruments made of wood is anywhere between about 40-55% relative humidity. At normal temperature. (And that last bit is hugely important too...) It's a range. If you hit 39 or 56 you don't need to hit alarm bells.

But why does this matter? Well - wood is a natural material and changes in temperature and relative humidity can affect how the wood behaves - mostly in terms of expansion and contraction of that wood. You see  a wooden ukulele absorbs and releases moisture and, being a very technically built thing that relies on build accuracy for tuning, that absorption and expansion can affect various parts  that matter. In the simplest cases, it will throw tuning out, but in the worst cases it can BREAK an instrument.. fatally. But here is the important thing. Most people bang on about the perils of low humidity - but high humidity can also be a problem! Humidify a uke that doesn't need it and you can also damage it.

Before we get into the details, first of all a couple of circumstances in which you probably don't need to read on with..

1. Laminate instruments - generally speaking, high or low humidity is not going to damage these instruments. Sure, I say 'generally' but by that I mean, 'so long as you don't leave them out in the Nevada sunshine or under the dripping leaves of an Amazonian rainforest'. Pretty much all other normal circumstance - you will be fine and don't need to buy a humidifier device. In fact, if you are prone to leaving your instrument in the Nevada sun or in a rainforest, you have bigger issues to deal with in your ukulele life... Humidity mainly affects solid wood instruments.. (and no, all plastic instruments are not affected either...). Saying all of that, humidity, both high and low CAN affect strings and throw them out of tuning or intonation temporarily. Still, there is no real need to worry about humidity with a laminate unless you are at the extremes.

2. If you live in a temperate environment with a natural humidity in the 40-55 range. There is NO need to worry so long as you keep them stored carefully (more on that later). Bear in mind that includes HUGE swathes of planet Earth, most of Mainland Europe and large parts of the USA. I've owned solid wood guitars and ukuleles for over 35 years and have NEVER bought a humidifying device. Guess what? Never had a problem.  Never. But then I have treated them carefully... PLUS I live in a very temperate zone.

So, for many people these devices are just not required, yet shops and would be 'experts' will instil fear and worry into players which lead to a  bunch of risks - either spending money you don't need to spend on more 'stuff' or damaging your instrument because someone online said so. Taylor Guitars famously started including leaflets with their instruments because (I believe) people were taking bad advice, over humidifying their guitars, warping them then trying to claim on the Taylor warranty for their utter stupidity.

Yet, it must be said, many people DO live in areas of genuine low humidity. What can happen to a solid wood instrument if it is kept in such a place for a long time with no care?

Classic symptoms of a dry instrument may include:

- Strings getting closer to the fretboard (low action)
- A sunken top - the bridge area dipping
- Sharp fret ends
- Joints in the wood showing cracks
- Splits in the top of (or anywhere) on the body.

So for those people at risk, devices are available to put moisture back into an instrument. They are basically sponges, foams or gels that hold water and release it slowly over time, sitting in the case or in the sound hole (when in the case). Kind of like cigar aficionados use to keep their smokes in tip top condition. If you live in an area of low humidity I would naturally recommend them. But that is not really why I am writing this. You see, there are some other things you should bear in mind. Bear in mind that leaflet Taylor wrote..

Firstly, applying humidification to an instrument that is normally kept in a temperate environment (and therefore doesn't need it)  can also damage it really badly. If you have been applying humidification when you didn't need to you may note things like:

- Strings raising high in action
- Strings themselves going out of whack
- Swollen top and back of the instrument
- Warped necks
- Bad neck angles
- Lifting bridges, frets, joints etc

In fact - the same sort of damage as for a dry environment, only without the cracking - but damage all the same, and damage that can be just as irreparable. And it is much harder to revive an instrument that has taken on too much moisture!

But there is another factor that comes in to play - and that is temperature or rapid changes in temperature. No matter where you live you should treat your ukulele carefully and follow some rules. Rapid changes in temperature can kill an instrument, regardless of humidity. The rules seem obvious, but they are worthy of repeating:

- Keep a ukulele in a case whenever you can
- Do not store them in direct sunlight or next to a central heating source
- Do not store them in hot cars
- Do not store them in cold environments

If you do any of those, no matter what steps you have taken to protect against humidity issues, you are likely to destroy or at least damage an instrument if you then move it to an extreme the other way. The classic error is leaving a uke in the boot of a cold car then carrying it into a warm house or venue. CRACK! I've seen (and heard) that happen first hand.

But I digress... This was about people shilling the need for humidifiers that are not always needed and people ignoring the damage that can be caused with over humidification. So to sum up...

- If you think you have a humidity problem - buy a humidity reader and test it before doing anything else. They are cheap to buy. Don't assume you have a problem just because 'Bob the ukulele expert' tells you that you do. Don't humidify an instrument for the sake of it! Ever.
- If you check your relative humidity over a period and it sits in the range of  40-55 (ish) you are fine so long as your storage choice is sensible
- Don't keep the uke next to a heat source
- Don't keep the uke in extreme cold
- If you DO live in an area of low humidity - get a humidifier device. But DONT be tempted to if you don't.


  1. from what i understand what really does a wood instrument in is fast changes in temperature and humidity. Leaving in a case will definitely help with sudden swings. Those of us who live in arid and desert climates, especially higher elevations are the ones who need to watch out. I would think that your local guitar/ukulele repair shop might be able to tell you a bit about how local conditions are. Just make sure they aren't trying to sell you something. Around here (colorado) I've seen more than a few with splits behind the bridge at places that do repairs.

  2. Best thing to do is keep it out of sun and away from extremes and in a case. Then buy a humidity gauge for the house and measure it over a few days. If it reads in the 40-60 range or so - do nothing. Humidifying at that range is not needed.

    Yes sudden swings can be fatal, but equally long term storage at low humidity can damage them too.

  3. Hi!
    I'm from Sweden. I thinking about buying a second hand Ko'olau ukulele from Thailand. The humidity in Thailand is much more than in Sweden, especially during winter time. Will that cause any problems for the instrument going from a high humidity region to a low humidity region?
    Merry christmas and thanks,

  4. @linh - at the end of the day - instruments that are prone to humidity damage (both guitars and ukes) do travel around the world all the time. My advice is it should be fine IF you take the following into account

    1. on arrival - leave in open box for 24 hours to acclimatise to your environment
    2. Keep in case when not played
    3. Keep away from heaters, sunlight, air conditioning - anything that generates an extreme either way.

    I live in a temperate area, but have had ukes from Hawaii, Nicaragua, Thailand, all over really - never had a problem if you treat them carefully

    1. I live on a greek island with 70% humidity...I stored my solid wood ukes in soft and hard cases after playing...normally I open them every day...but when I was not able to play them for a few days they got damaged from humidity in the closed case...they all have very tiny black spots in the wood grain...outside and inside...I am so sad this has happened...DJ Morgan...KoAloha...Kanilea...��

    2. I know this comment was in 2019 but that's interesting. Bad of course for expensive instruments. Somehow makes me think of a fridge that's been turned off and the doors left closed then later finding out mould has developed because the moisture inside the fridge wasn't allowed to dry out. 🤔

  5. The humidity gets pretty low in the winter here in Michigan. Still, I'd never had a problem before this year, my zebrawood uke cracked! It was repairable, but I started humidifying my nicer ukes after that. Probably just during the worst of Michigan's cold weather. The repair fella theorized the wood they used wasn't cured completely.

  6. Damn it, Baz! Will you never leave off being reasonable and correct? How will charlatans ever peddlle their useless crap with you around? Spot on. Don't spend money or take unnecessary (potentially harmful) measures to "solve" non-existent problems.

  7. ha ha! You know what though Lan - I swear some people only read the first line of some of my posts before they get offended and call me out as being wrong. Had someone today write me a diatribe pointing out exactly what this post says...

  8. So many instruments these days use woods for there aesthetic appearance rather that there suitability as a tone wood or structural wood in ukuleles. Some of these exotic woods do split more easily than say Mahogany or Koa. As a wood turner I love to use spalted woods, but spalting is the effect of a fungus that is the first stage of the wood rotting, it therefore has weak areas. looks wonderful, but suitable as a tone wood, I wonder.

    1. I had the exact same conversation with another luthier I know Chris - his view was it was not suitable as solid tonewood. Laminate version, yes, but not straight up solid pieces. Too likely to split

  9. Hi Barry, thanks for writing this piece. My concern is that while I too live in a temperate environment here in Portland, Oregon, the old house itself is very drafty, and I have to use a room dehumidifier during the rainy months (this year has been particularly soggy). This equates to quite frequent humidity fluctuations inside the house. Because of this, so far I have mainly purchased laminate ukuleles, and keep them in their hard cases when not being played. (I also have a couple plastic ukes and cigar box ukes as well.) Although I would like a nice solid wood ukulele, I am not sure how well they would hold up here so have refrained from getting one. Am I being overly cautious?

  10. It's hard to say Joneo but you are absolutely right - stability away from fluctuations is incredibly important. But bear in mind that a lot of very high end instruments are played and even made in both some very humid and very arid parts of the world - it's all about the storage.

  11. Hi Barry,

    Just checked some history for Maidstone in Kent and relative humidity goes from about 60% in June to 85% in December. Is this the same humidity scale you mention in your article, and as it's way above the 40/55 should I be worrying?
    Web page,maidstone-kent-gb,United-Kingdom

  12. That is high, and the same scale. But I wouldn't rely on weather station recordings - I very much doubt it gets that humid inside your own house - and that's the thing to check. The only way to be sure is buy a hygrometer (not expensive) and record the humidty in the room you mainly store your instruments.

    Either way, if you are getting up that high there is no way you need to humidfy your instrument!

  13. Hi Barry, might just do that.
    I've got a friend who keeps one of those little silica gel pouches inside his ukulele cases.
    Do you think that this a good idea or not?
    (Reply link doesn't seem to work)


  14. To take the humidity down - yes, but be very careful - important to check exact humidity you are dealing with. End of the day, even high humidity is kind of normal, when you consider the ukulele originated in islands like Madeira and then Hawaii

  15. So what should somebody do if they live in a place with higher humidity? I just bought a koaloha ksm-03 from mims who is in Virginia and had it delivered to me in south western Australia where the humidity is around 60 to 70 percent all year round?

    1. 'Possibly' consider a de humidifier unit for room Ukes are stored in. But it's about of a balancing act to not go too low!

  16. Slightly different issue that though. That’s mildew..

    1. Can you give me a hint how to remove this mildew please?

    2. Not sure I’m afraid. Mildew is a fungal spore issue, and whilst connected to high humidity I don’t think is harmful, yet is unsightly. Never seen it on a ukulele myself,


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