Intonation problems.

[sgcim]

It's been very humid here (dew Point 73!), so maybe that's a factor. I've been using those Sadowsky strings that some of us bought when they were closing their string business, as replacements, and they play sharp, while the old TIs seem to be okay.
Adjusting my wooden bridge seemed to be impossible to get everything good.

Is this just typical Summer problems, or the strings? The neck on my Borys Jazz Solid looks straight.

[wintermoon]

I've been using them and my guitar is always sharp when I pick it up but I attributed it to the hellish humidity we've been having.

[sgosnell]

Looks straight? Have you actually measured the neck? Humidity and temperature certainly affect guitar necks, and sometimes the relief needs to be adjusted. Fret a string at the first fret and at the fret above the neck join simultaneously (a capo can help with this) and check the relief in the center between them. A straight neck will have very little gap between the bottom of the string and the fret. I like only a couple of thousandths, closer to one, but others like more. Or you can buy a straightedge from StewMac if you have lots of extra cash. The string at tension is straight, though. If the frets aren't perfectly level you need more relief to avoid buzzes on the higher ones. All that said, it might be the strings. Can't quite tell from over here.

[whiskey02]

I'm thinking somehow in the above posts that intonation is being confused with tuning. Have you tuned all strings, and as you go up the neck octaves are sharp....or you pick up the instrument and the overall pitch is 13cents higher than when you last walked away so you have to loosen each string half a turn and then bring each string to its correct tuning and then everything is okay? That's two different subjects.

[rpjazzguitar]

If you tune the guitar with a tuner and the intonation is off at the 12th fret (fretted note vs harmonic), then you have to do a setup.

There are lots of good videos. I liked the Fender setup guide, https://fendercustomersupport.micros...ticle/KA-01901. It's targeted at Stratocasters, but there's a lot of material therein applicable to setups in general.

First off, new strings. You can't do a setup on old strings.

Then, the various measurements and adjustments to get the neck right.

Then adjusting the bridge. Position, saddles if it has any and height. For bridges on posts make sure there isn't any play because the post is a little too small for the hole. Often overlooked and can drive a person batty (don't ask how I know).

May adjust pickup and/or polepiece height.

The tools required are usually a metal ruler in 64ths and or mm, a screwdriver or two and the wrench for the truss rod which may have come with the guitar. Otherwise you have to find the right one. A string winder is a nice convenience.

And, that should do it. If it doesn't, it's over my head. That supra-cranial area includes all manner of nut, saddle and fret filing and arcana such as neck resets and woodwork.

[sgcim]

I'm thinking that wintermoon is right , as usual. The humidity was insanely high yesterday, and the dew point was tropical!
Today things went down , and it's playing in tune again. This has happened before, and it's been a while so I forgot about it.
I only have A/C in one room, and I leave my guitars in the room without A/C.
Maybe that has something to do with it.
I've got a show coming up in less than two weeks where it opens with solo guitar for a number of bars, then the singer comes in, for about eight bars, and then the band comes in 8 bars later.
If the pitch is bad, it should be a train wreck.