Best np-fw50 in cold weather?

Skiing with a NEX5t in Montana. On warmer days it's fine, but cold days (~10°f) they die super fast. I have one older sony and one brand new kstar, both seem to have issues with cold temps. This camera lives in my outer vest pocket while skiing for easy access. I could bring a spare but today 100% at the house was dead in less than an hour outside. Looking if any of the newer options are any good for cold temps specifically? upgrading the camera is not an option as I want a NEX5 of some variety because it's enough smaller to be worth it.

These were what I'm looking at:

Thanks to anyone who knows if any of these are better specifically for cold temps.