I like to hunt when it's warmer, and when the sun is shining. Once I'm in late season, no more early morning daylight hunts.. I'll slip out around, 930-1000 and hunt until lunch time, then maybe go out early afternoon again. When the weather is nasty I stay home, because the squirrels probably are too. It's hard to beat a nice sunny late January day. As the woods warm up, they come alive. Also, focus on where they were feeding earlier in the year. They'll be running around digging in the snow looking for their stashes. I usually just try to find a nice looking log, then sit down for a while. If I don't see anything within a half hour I'll move.
-Jake