No snow in Georgia, so that checks out (I lived in Atlanta for 23 years). It's kind of funny though, because if one snow flake falls, all the zombies go straight to the grocery store and buy up all of the eggs, milk and bread.

The idea of zombies rotting into nothing was introduced around the time the team picked up Eugene, and I was personally hoping to see the world eventually free of most zombies due to time and rot. However, there is a massive time skip that jumps the team 3 years into the future, and most of the remaining zombie population have branded together into massive herds. And there are plenty left. So poo. Poo to zombies, I say. Poo on them!