I'm not sure it's the phone...it might be the micro-SD card, but I've tried two. Can't remember which, one was a Sandisk and the other was a good brand too. I thought I was done with the problem a few months ago when I swapped to a new card, but then last week it crashed on me. Just frustrating.
Do you use a screen protector? A friend was saying screen protectors affect the phone's use in cold weather.