Hmm, that is interesting. It has been working perfectly since the issue and still doesn't need to be recharged. I suppose it could have been a combination with the ipod also being cold. When I tested my RE0 directly into the ipod it had been inside for awhile. I'll see if I can replicate the problem within the next few days. I was outside today for about an hour using it (36 degrees) but I had it in my down coat this time.
If you mean farenheit it shouldn't be a problem. I've used my ZO for 30 mins in -15 C with no problems.