If there would be seasons there could be special Zombies for every season. And I don't talk about Zombie bikini girls and undead red nosed Reindeers now....
Oh, wait ... Zombie bikini girls?
Typical example would be Zombie bears. Most likely you would see them in Spring, when they are even more aggressive because of hunger, and in Summer - but not in Winter. In Winter you'd probably see more roaming Zombie wolfpacks.
Like in Subsistence seasons could also effect your stamina (heat slows you down and dehydrates you quicker). When there is more rain in autumn, you can find more water then (puddles), but in Summer you can cross lakes on foot because of the low water level. And so on...
You get the idea.
And, most important: Can we have hordes of Zombie bikini girls please?