All of the previous posters have excellent comments and reasoning. The variables definitely do dictate when the deer are moving. However, I am with SSGJB though and say just hunt all day! Seriously I used to be one that left the woods/fields during "lunch hour" and would come back in later in mid-afternoon. Not any more. Like Critter I now plan from before sunrise until after sunset to be hunting. I especially like being actively hunting whitetails right around 1pm because that is when most of the hunters come back into the woods after their lunch break and push the deer towards me. So I would say whatever you need to do to get into the woods or fields based on your personal situation - just do it! No matter the time spent make it quality time - am or pm.