Some may wonder why George is as buttoned up for the cold as John…
Various sources have stated that Zombies freeze in cold temperatures.
The Zombie Research Society Blog has an article Do Zombies freeze in cold weather?
Max Brooks also mentions it in the Zombie Survival Guide and World War Z.
Because a zombie’s blood doesn’t flow throughout his body, due to him being ‘dead’ they’re highly susceptible to cold temperatures.
It’s one of the reasons George wears a turtle neck all the time.
-John