I can glass the edge of 900,000 acres of national forest/mountains. I glass for critters several times per week, year round. It gives me an idea of what elevation elk and deer are holding at. That way when I head into public land with tags, I know what elevation to start at.
Based on what I see, it's two fold.
#1 Elk in natural undisturbed state. Temperature, Snow, wind, and water determine what time of day, and where they go.
#2 People, Wolves, and other disturbances.
Wolves have changed the patterning of hunting. I've glassed big herds for weeks waiting for the big bulls to come around so I can get a shot at one. Then one morning hundreds of elk were simply GONE. And I saw six wolves, having a wrestling contest where the elk were bedded the day before.
How elk behave in a protected environment, like private or a national park will not match public land elk.
Migration is not based on the calendar or clock. It's based on need.
My determination is, there are too many factors to consider to know what a wild animal will do. Only details to increase your chances of finding them.
I watch elk year round. And It still seems random.