At the time of Apple's iPhone 3GS' release, it was considered hot. But today its heat is pestering its users.

Though Apple hasn't issued any formal statement regarding reports of overheating iPhones, still Apple has come up with a set of guidelines to help iPhone users ensure that their devices remain fit & fine and operate well.

As per issued tips iPhone 3G and iPhone 3GS should only be used in environments where temperatures stay between 32 degrees and 95 degrees Fahrenheit. Extreme temperature could affect devices adversely.

The concerned devices should not be stored at places where temperatures lie outside -4 degrees and 113 degrees Fahrenheit. 
 
Users should not leave their iPhone in a sealed vehicle as temperature inside the vehicle could exceed 113 degree Fahrenheit. 
 
Moreover, one should not try too many applications at once on a hot day as your iPhone could become overheated.

And the last but not the least, if your iPhone gets too hot to handle for long, turn it off and let it cool down.