Never try to tune a piano when brought from inside to direct sunlight!  You'll pull your hair out, the piano will go flat in 5 minutes, and never stabilize.   DAMHIK!!  Temp swings inside a home or building aren't a drastic, but...same thing.  Whatever you do at 70 degrees will change if the room moves to 60 or 80.  Mild temps swings will do the same, but take longer.   Don't go into a cold church when they want to tune "to the organ" (another nightmare as you won't know what temperament it's in and neither will the office people).  Organs will go sharp as they're played on Sunday, and the room will change in temp and humidity as well. BTW: Welcome to the PTG.  Good luck on your new adventure! Paul <table width=100%> <tr valign=top> <td>From: <td>Ron Nossaman <rnossaman@cox.net> <tr valign=top> <td>To: <td>pianotech@ptg.org <tr valign=top> <td>Date: <td>05/09/2011 01:37 PM <tr valign=top> <td>Subject: <td>Re: [pianotech] Experiences of Temperature on Tuning        Stability        Inquiry...</table> <hr noshade> <tt>On 5/9/2011 10:17 AM, Zachary LaMotte wrote: > Dear Fellow Mailing-List Members- > > I am Zach LaMotte (current student at CSPT and newly applied associate > member for the PTG!).  After extensive research on past discussions in > the forums, I have found a lack of talk on the effect of temperature on > tuning stability.  I am well-read on the impact humidity plays on the piano. This comes up a couple of times a year, and we've been over it many times. String pitch shifts immediately with temperature change. The wire elongates as it warms up, shortens as it cools, changing tension and therefore pitch. Eventually, the plate will catch up and the piano will be pretty close to the state of tune it was in before the temperature shift. Tuning with furnace or A/C outflow blowing in the piano, or the sun shining in on the strings through the clouds intermittently, means the pitch will drift up and down as the unit (or sunshine) cycles, throughout the tuning. None of this has anything to do with humidity, as humidity induced tuning fluctuations typically take days, not minutes. That's pretty much it. Ron N </tt>