Why do deer move when cold fronts come in?

Why do deer move when cold fronts come in? This question was asked recently by a friend of mine. Thinking about it we all know that deer tend to move more when a cold front comes in, but have I have never really taken the time to think about the reasoning behind this.

Some researchers believer that it is the food that brings the deer out. Deer need food just like us humans to give us energy. I personally do not believe in this idea as much for the very reason that  deer convert the energy in carbohydrates to saturated adipose fat. This fat is the fat that is burned for energy. Marbling fat is the fat that is produced during the summer time along the muscles.
Other ideas are like us humans as well, do we want to go outside and play when it is 90 degrees without a shirt on? I think we would all prefer to go out when it is about 70. Deer have two layers of fur, a winter coat, and a summer coat. Come fall a deers' fur thickens up to the winter coat. With this coat deer don't want to come out with it is hot, they prefer when the cooler temps move in.
With this thought I am heading up to Iowa tomorrow and a major cold from came through. the high was mid 60s and the night it is getting down to 29. I am going to sit in the box blind and watch and hope for deer to be out and being active since the temperatures at their ideal level.