I'm not that far from you, so I'll guess the same holds true in your neck of the woods. This time of the year, squirrels will mainly move right at daylight, and then right before sunset. I don't know if it's because there are no leaves on the trees and they can see & be seen better, or it's the cold, or if predators are more active now. I've always noticed squirrels are active most of the day in September & October.