Hm. That is indeed odd. I play banjo and those strings are thinner than guitar strings and you’re right, they always loosen. Perhaps it’s the temperature?

Could something have caused the wood to stretch? Moisture, maybe?

Admittedly, I do not make great effort to protect it from the crazy humidity here.

But I’ve had this guitar for over a year. It was used, when I got it.

It has not displayed any neck issues, other than some vibration on deeper notes it’s fine.
I like the action, and I just never took it anywhere to get it professionally adjusted.
It still has the same strings it had when I bought it.
I bought new strings when I got it, but really like whatever it’s stringed with now.
The strings are not shinny. Bit they don’t look near as old as they are.

Like I said, I stretch my strings frequently.

It was “in tune” two days ago.
I played it probably 3–5 hours since.
I picked it up today, and it sounded off. Checked, and every string was too high.

It was so weird because I was watching the sound vibration on the tuner, and when I saw it so far off I instinctively tightened the first key. But it didn’t bring it back, I noticed everything was too high.

Damndest thing!

Lot’s of humidity possibilities, but I can’t imagine it changing so fast. It’s not even “hot” here yet. There was a bad storm last night. That would change barometric pressure, and some other things, but that’s really reaching.

@Jeruba Hypothetically, if the neck stretched back it would tighten the strings. But. The action is the same. Or, the strings seem to be the same distance from the fretboard.

It’s not like I’m going to lose sleep over it, but I’m curious how it could have happened.

I was diligent in tuning it two days ago. So. I don’t think I somehow tuned it too high, played for hours without noticing and then the same tuner wasn’t inaccurate today.

I’m officially flummoxed.
And vexed. Yes. This vexes me.

This is when you point to gremlins.

^I’m not even kidding, I lost my remote to my TV in the same time span. Where I found it, it just couldn’t have been there…

Great. So now, I have gremlins.
My mother’s chihuahua looks enough like a Mogwi, this is more plausible than I am comfortable with.

If the temperature was significantly colder than the last time you tuned, it could cause the strings to contract slightly resulting in the tune to go up instead of down.

I tune mine everyday. Typically they are a bit loose. If they all are tight the truss rod may need adjustment. The neck will expand and contract with the weather change.
The humidity level can affect the guitar significantly, additionally the strings may have lost their elasticity. Yet its not likely to happen all at once,

This is a symptom of a guitar that has a detached/loose or improperly adjusted truss rod. This can also happen with significant temperature and humidity changes, especially if it’s a cheap acoustic with no truss rod. I would also take an index card and see if it can slide underneath the back of the wooden bridge piece where the strings connect. If it does slide under it it’s loose. When one of the higher tension strings like your big E detunes flat it will actually make the other strings detune sharp if this is the case.

It actually does have an adjustable truss rod.

I bought it at a great price as damaged, at Guitar Center.
Some nice person somehow put a good hole in it.
I was able to by the guitar for half it’s worth, and Guitar Center has a warranty program available.
So. I bought it broken, payed like $60 for a replacement warranty. That way I can get it replaced with a new one.
Even with the hole, it sounds so good. Maybe because of the extra little hole…

I haven’t had the heart to risk them wanting to take my guitar for a new one. I don’t consider it “cheap,” but I believe that Gibson will simply mail me a new one of this model.
I do consider it irreparable. Even the pickup doesn’t work.

There’s really no reason to just look into the warranty.
I could screw up the warranty if I adjusted it.
I’m not sold that’s the problem.
The bridge is good.

I am nearing the cut off time for the warranty anyway. I was mainly more interested in what would cause the problem.

Many thanks to all who chimed in.

Get you a new one then!

^Well I knew the day would come. I just wasn’t ready to send my instrument off to possibly be euthanized.

The humidity and temperature in the room affect the guitar itself causing it to expand and/or contract some.

The strings did tighten again some.
I put a bag of moisture collecting silicone in the guitar.
Obviously, that’s not the same as the environment, but it’s what I am willing to do.

I’ve owned I would think sometimes like a dozen guitars in my life. Only three were electric.
Two were 12 string.
I have had these acoustics in the Islands, and here in Charleston SC, for decades and I can’t recall this happening before. I had this same guitar last summer (hottest on record.)

It’s still a mystery, to me, how the action seems unaffected. I agree that the only possibility is the humidity, I’m going to take a stab in the dark and hypothesize that the wood in one/all parts of the guitar may be different than my previous guitars.

Most of my previous guitars were pre-owned, and old. But. Some were made pretty well.

This guitar has a glaze over it’s entire surface. It occurs to me that most of my other guitars did not have a finish. I believe the gloss gives it a different sound.
This is an Epiphone. The design is Gibson. The product I believe is Chinese.
This is also my first Chinese made instrument.

I don’t want to piss off Asian people, but I believe they are capable of great craftsmanship.
I’ve had a couple from Japan, that I loved.
The possibility/likelihood of the wood being of lesser quality than advertised is very much in play…

Are there any suggestions for reducing the guitar’s exposure to humidity? I mean, other than a hard case.
I play it everyday, several times a day sometimes. Having to unlock it from a big case each time, would be cumbersome. I don’t have a large area to store things. The guitar sits next to the shotgun, and they just lean against whatever wall.

When I buy things for my canoe, I often go cheap with the possibility of it getting wet/lost is always there.
Should I just not spend over $600, and trade in when they go funky?