Originally Posted by
der_saeufer
Not a lot will help that other than finding a way to keep the phone warm--it doesn't generate enough of its own heat that a case will help much--particularly since anything that lets you use the screen lets heat escape through it unabated. The reflective pouches like the Phoozy are definitely better than nothing but there's no substitute for keeping the phone as close to a heat source (eg your body) as possible. Even if it's only 10C/50F under your jacket, that's way better than freezing the phone outside.
I spend a fair bit of the coldest days of Januaries on the icy cold and windy ski slopes of Upper Peninsula Michigan and the Swedish mountains. I don’t carry any special pouches for my phones to be used on the slopes and in the very much wind exposed lifts there, but I do keep the phone inside an interior pocket of either my ski jacket or inside of an inner layer. I could perhaps do marginally better to get more in-hand — in-glove really — phone use outdoors on the mountainside in the winter by having the phone in a pouch flush with my skin with a heated chemical hand warmer pouch in the phone carrying pouch, but it hasn’t done enough good for me or the phone to not just stick the phone inside an interior/body-facing pocket of my jacket or an inner layer inside the jacket.