Operate iOS devices 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 alter its behavior to regulate its temperature.
Read here > http://support.apple.com/kb/HT2101
Hope that helps
The Basic Troubleshooting Steps are:
Restart... Reset... Restore from Backup... Restore as New...
Restart / Reset
Backing up, Updating and Restoring
If you try all these Steps and you still have issues... Then a Visit to an Apple Store or AASP (Authorized Apple Service Provider) is the Next Step...
Be sure to make an appointment first...