We finally have some spring weather in DC this week and I got my Surface RT outside for the first time really since purchasing it last fall. Anyway, after a half an hour of use in the sun, the RT beeped, the screen went black and then a white stylized thermometer appeared for a few seconds before the screen went dark again. I could not turn the unit on until I left it inside for about twenty minutes allowing the unit to cool down. Anyway, that is the first time that has happened to me. I'll keep an Eye on it going forward.