We know that the new iPhone 3GS is stacked with all sorts of new features and an increased processor. However with all the good must come some back, or even discomfort.
There has been several reports of iPhone overheating and discolouring… mainly as Apple states to leaving the “device in a car on a hot day” or “Leaving it in direct sunlight for extended amounts of time”. As a result, Apple released a statement for all iPhone users on how to effectively operate your new iPhone within “acceptable operating temperatures”.
They say “Operate iPhone 3G and iPhone 3GS in a place where the temperature is between 0º and 35º C (32º to 95º F). Low- or high-temperature conditions might temporarily shorten battery life or cause the device to temporarily stop working properly.
Store iPhone 3G and iPhone 3GS in a place where the temperature is between -20º and 45º C (-4º to 113º F). Don’t leave the device in your car, because temperatures in parked cars can exceed this range.
If the interior temperature of the device exceeds normal operating temperatures, you may experience the following as it attempts to regulate its temperature: The device stops charging, Display dims, Weak cellular signal & Temperature warning screen appears with the message “iPhone needs to cool down before you can use it”.
More here at Apple