I have some dedicated practice space in my mostly finished out basement. It's got carpet, drywall and some sound proofing, but not heat or air. Seattle is usually pretty stable humidity wise, but we did have a clear spell and it just started raining again. Not a dramatic weather shift. When I went down to practice last night all 4 strings were almost a 1/2 step sharp. I had been out of town for a few days, so I had last tuned it probably 3 days earlier. This struck me as odd. Has to be either the weather change or a mischievous gnome playing games with me. Anyone have information supporting either theory?