Different roads make a difference, too
Different surfaces have different characteristics. Some are smooth, almost polished, and that makes it hard for tires to grip on to anything while you're accelerating... which hurts a 0-60 time. Others have surfaces with grooves that a tire's great at gripping. If car A and car B both have 0-60 times that are even remotely close to each other, and you don't know exactly how those times were set, you still don't know which car is quicker.
And that's not to mention the impact of temperature, or even the altitude
Engines like cool, dense air -- it helps them make more power. A cool day at sea level is a very different prospect than a warm day in, say, Denver, where the air is notoriously thin. Don't underestimate the effect that has on a car's 0-60 time. There is such a thing as too cold, though, because a tire generally won't like cold weather. After a certain point, it becomes hard, and it's like trying to drive on a different set of tires all over again.