I've often wondered if they knew going south would lead to warm weather.
"The oldest human remains in California, maybe in North America, were found just a few miles from where I live in the Channel Islands. Arlington Springs Woman."
Arlington Springs Woman is the oldest skeleton ever found in the Americas. Previous to this accurate dating Luzia (Brazil) was the oldest.
"So was a pygmy mammoth (which seems to excite researchers much more than the significant human remains!)"
Some believe those pygmy mammoth bones had been cooked.
There's no way to ever truly know, of course, but I think they did. Those ancients were close observers of nature and I'm convinced they understood at least the essentials of celestial navigation and the north/south climate concept. Also I believe their travels weren't simply one way, and after the first hardy souls arrived south of the ice, some went back to spread the word.