Just wondering because it seems like I have perfect flight one day, then when I shoot a few days later it may seem not great no matter what I do. Then good again another...

Obviously this could be user error, but my gut says it's brace height due to weather changes.

What do you guys know about that?

Measure when it's good, check it and adjust accordingly.  How often depends on a lot of variables--string material, strand count, draw weight, temps, etc.

I check my brace height regularly and have not noticed fluctuations due to weather. When I get what you are describing it is my form inconsistencies showing up-could that be happening to you?

I don't know how much it would actually affect flight, but it makes sense that weather could affect brace height.  

I did hear a neet trick recently that I'm going to try.  Mark your arrow with a pencil at the edge of the shelf when you get your brace height just right.  Then paint a crest ring at that location on each of your arrows.  This gives you a quick easy way to check brace height in the field.  I'm getting ready to crest some arrows for the first time and I came across that tip while reading up on different cresting methods.

Matt

Great idea Matt. Keeps me from carrying a ruler in the field    

What a cool idea Matt. It definitely is probably my form. But I have heard to measure your brace height etc. but was not sure what kind of precision we are talking about. When you measure it, does one twist actually change it much? I ask because it seems like it wouldn't, however, one or two twist seems to be noticeable on my bow.

Hot weather or leaving bow in the sun can cause the string to creep, how much it creeps has a lot to do with string material and the quality of the string build. I check mind regularly when it's a new string and then every once in a while after it's shot in good. Don't usually make adjustments till it's out 1/8" or more unless I plan on shooting broadheads.

Or you can just make a "thumbs up" fist and lay it on the same spot on your riser and remember where the string touches your thumb.  Or how far above your thumb it sits if you have small hands like me.  I check mine often as well but once the string has been shot in it rarely moves.

I take note of where the arrow touches the riser every time I shoot and adjust when I see any changes. The cresting ring is a good idea. Maybe sharpie so you can wipe off with alcohol if you wanna make a change?

Hummm....

Not once in 6 years. My Cheyenne's been strung all that time & shot to heck & back. I set it at 7¼" then & it' s still there now.

Leave your bow strung after setting brace for a few days ,check it, twist it till its right,wax it and rub it in with leather and friction and leave it strung till it's set and it should stay.(or leave it strung like robtattoo and me)

I use the crest that's on the wood arrow to match my brace height

I recently got a new string from HHA.
  I put it on let it sit strung for a day and then set my Brace, It has not moved since.
  My Brace height check tool, Is a piece of Broken arrow, Cut to Brace height, Nock the tool on the string and the cut end touches the grip.
  I keep it in the bottom of my Quiver...

After a string's been shot in and quit stretching, I check it occasionally, but it doesn't change.  If it was moving on me, I'd find another string.
Rob,
Have you been shooting the same string for 6 years?