I tested my 350 outside for an hour with the temperature at 90 degrees F, the humidity at 45%, and the heat index at 93 degrees. After about 40 minutes I did notice a slow down in page turning speed, and then used a stopwatch to time it. The page turns slowed to about 1.5 seconds in duration including the finger swipe on the screen. This is about identical to the issue I read concerning the new Kindle 3. No other slow down or erratic behavior was noticed.

My conclusion: At worst, I find this to be a very minor issue. I can live with 1.5 second page turns when in the heat as I will seldom be reading in that temperature. And let us not lose track of the fact that Sony rates the reader for up to 95 degrees F, so we were taking it to the edge of its design parameters. Therefore, we should expect issues at this temperature. And the same can be said for the K3.