[RyteSyde]

perhaps the anti-rattle clips need to be pulled off and bent wider, then re-seated. Just thinking out loud, when they're not quite right but as they heat up, they expand enough to keep the vibration at bay. May be worth re-seating the pads and checking the clips.

BTW how are you liking the spindles?

 

[RyteSyde]

It just sounds like expansion of some sort, that's why I lean towards the rattle clips. After you brake a few times the heat causes them to expand so no more vibration/squeak. When it's raining, water vapor evaporates from the heat, cooling it and the surrounding area down much faster, hence less expansion/more squeak. If it were contamination it should stay constant or get better over time, not come and go no? On top of that, it started after you took them apart so my money is on the clips. Then again, if you couldn't tell by my gameroom cash, I'm a horrible gambler