Apple issues "common sense" heat advice for iPhone 3G/3G S

Do iPhone 3G and 3G S handsets overheat during regular use? According to unconfirmed reports iPhone 3G S handsets can get get hot enough that they turn pink. I've not see one first hand so it's hard to confirm the reports, but it seems that the reports/rumors have prompted Apple to issue an advisory.

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" 

There's also some suggestions as to activities can raise the temperature of the iPhone:

Some conditions and activities that may activate the Temperature warning message:

- Leaving the device in a car on a hot day. - Leaving it in direct sunlight for extended amounts of time. - Using certain applications in hot conditions or direct sunlight for long periods of time, such as GPS tracking in a car on a sunny day or listening to music while in direct sunlight.

Then there's a section of safety standards that that the iPhone conforms to.

I don't use an iPhone but I have noticed that the iPod touch can get hot sometimes, but not hot enough to cause problems. My own cellphone, a Nokia E71, also gets pretty warm at times, especially when using the video phone feature. I have upgraded the batter in my E1 to a Mugen Power high-capacity battery, so this might be what's causing it to warm up.

It'll be interesting to see if this turns out to be a fault or just some random incidents. The fact that Apple has issued an advisory is curious though. Maybe the 3G S is more susceptible to overheating than earlier models.

[UPDATE: Seems that this issue might be down to people using third-party cases or skins. This seems like a plausible explanation because I have seen the effect that skins and cases have. I once came across two identical cellphones, one with a skin fitted and another without, where the skinned cellphone (a Nokia) felt much warmer to the touch than the unskinned handset. Other factors (charging, battery capacity, ambient temperature ... can also contribute to overheating.]