Alright, good to know! Thank you all so much for the advice!

Putting humidifiers in a closed case isn't such a good idea in dry climates (or any climates) as you've seen majajog.   Keeping a dulcimer in its case anywhere is not particularly good for them, either.   When you're in a dry climate like Arizona (I lived there for a number of years)  the best thing is room humidifiers, even if it's just a sponge in a bowl of water sitting on the coffee table. 

We spend the winters in AZ where the humidity gets to 6%.  We keep what was sold to us as guitar humidifier in the case to keep the instrument from drying out too much.  Never had any problems but don't really know if the humidifier helped or not.  On the other hand we still had the humidifier is the case when we got to Arkansas and the humidity was 95%.  Opened the case one morning and two of the strings had broken in the case during the night.  Took it to the dulcimer shop and they said the strings had rusted through.  Apparently too much humidity!

Our neighbor also keeps a humidifier in her case in AZ and had three of her frets rise and the person that fixed them said it was due to too much humidity.

I guess I agree with Noah, that I worry about the instrument drying out too much when there is very low humidity.

We spend the winters in AZ where the humidity gets to 6%.  We keep what was sold to us as guitar humidifier in the case to keep the instrument from drying out too much.  Never had any problems but don't really know if the humidifier helped or not.  On the other hand we still had the humidifier is the case when we got to Arkansas and the humidity was 95%.  Opened the case one morning and two of the strings had broken in the case during the night.  Took it to the dulcimer shop and they said the strings had rusted through.  Apparently too much humidity!

Our neighbor also keeps a humidifier in her case in AZ and had three of her frets rise and the person that fixed them said it was due to too much humidity.

I guess I agree with Noah, that I worry about the instrument drying out too much when there is very low humidity.

Having lived in hot-humid climates worse than Hawaii, and currently living on the water on the Gulf Coast of Florida, I can say this -- when you move from wherever you are now, you dulcimer will adjust to the new local humidity over the span of a few days to a week.

 There may be some minor issues -- I had a fret raise a bit when I moved from dry Colorado to ultra-humid Kwajalein Atoll in the Pacific just north of the equator.  When I played my dulcimer in my air conditioned living quarters it sounded fine, but when I went outside, after a bit that one fret would rise and I'd get buzzing.  I eventually took it to the island hobby shop which had the fine tools necessary to pull and re-set that fret.

That's the problem if you live in the tropics and insist on deep chill air conditioning (which also de-humidifies the air) -- when you move from indoors to out (and back again) you really need to give your instrument time (at least half an hour) to adjust to the new conditions.  Keep your AC around 78-80F and those transitions are much less -- both on your dulcimer and on your own body.  Most Americans set the AC 'way too low -- 68-75 is 'way too low.  Learn to live closer to your natural environment and you and your instruments will be a lot healthier!

 IMO, low humidity is more of a danger than high.

Humidity will affect most woods the same way. The wood will swell then contract if quickly (for a long period of time) put in dry weather, resulting in cracking.

I have never experienced humidity problems with any of my instruments. My dulcimer stayed in a humid climate (Alabama, Georgia, and Florida) for twenty years. Never had a problem with it cracking because of humidity.

Just make sure it stays in your house for most of it's life and that your house's air conditioning doesn't get turned off with it for long periods of times.

If other people say that Hawaii's humidity is greater than the 100% humidity of Florida, you can keep it in a case and they make tools to take and give humidity to instruments.

So if you play it outside A lot (like ALOT like 15 hours like Mr. Ken Longfield said) you might have trouble once you bring it into a SUPER Dry area.

More than likely you will have no trouble though!

Like most people, most instruments would be most happy in Hawaii.  

Humidity swells wood. A well constructed dulcimer should not suffer from humidity. If you are going to play outside in high humidity for 14 or 15 hours a day, you might have a problem. If you play mostly inside in a humidity controlled environment, you should have few, if any, problems. My philosophy is that if you are comfortable, your instrument will be comfortable.

I wouldn't over matter much about this.

Ken

"The dulcimer sings a sweet song."

Hello all, I'm thinking of moving to Hawaii. Does anyone have any insights on how humidity would affect mahogany dulcimers? Is another type of wood better? Is there a specific way I should care for my instrument? 

Thank you in advance!