Depends on where you're at. Later this week and into next week (in the northern part of the state) we are looking at highs in the 20's and lows in the teens. The roads will be pretty firm. The next few days, however, it will be wet and above freezing during the day, which = sloppy mess.
Personally, I would go with the 4wd, even if the weather forecast was better. Minimum maintenance roads, roads along sloughs, etc., can all call for 4wd at times.