[Gallagher]

If decomposition is in play, then they would break down significantly faster, maybe in as few as 2 years instead of the 5. In contrast, heat wouldn't really delay them as much as snow and cold, so I'd put my bet on ones with more energy, so they'd be more dangerous while they do last. Most especially in areas with plenty of wildlife (though that goes for more than warm areas) as, if their starvation gets to a point where they hunt animals (a possibility which must be taken into account, too), the more game, the less you can count on waiting it out.

Another thing to take into account here is the effects the weather would have on human survival. What places would be better for the production of food, where would the temperature allow for more armor in case of direct contact, how would you cope to the extremes. A nice winter place takes on an entirely new meaning if there's no electricity or heat, and it's dangerous to go out for firewood regularly.