Battery Drain and Overheat after 5 Minutes of normal usage

Hi there,

I am from Germany and during the last days it was extremely hot here (~35 degrees celsius). Since these days my iPhone 6 (iOS 8.1) loads the battery tremendously fast, but unfortunately the battery does not last for a long time. In fact, after 5 minutes of normal usage (whatsapp and email) I lose about 5% of the battery. In addition to that after about 5 minutes of holding my iPhone in my hands without a protection case it runs extremely hot, starting at the rear camera.

I have never had problems like that before. Has the hot weather maybe killed my battery?

Thanks a lot for your help!

Regards

cutting-edge