Ran the local Turkey Trot (5K) on Thanksgiving morning - temp was 32F with absolutely no wind. Pretty comfortable conditions actually. A light snow was falling for most of the race, but not enough to stick. I thoroughly enjoyed the run.
BUT...
Races like this come with their own problematic logistics for barefoot runners. With over 4,000 people in the race, parking is at a premium. I got there early and managed to park within a quarter-mile of the start/finish area. So I sat in the car until about 15 minutes before race time, and then walked to the start line. Parking lot was wet gravel (pretty uncomfortable to walk on at 32F). Then another ten minutes or so of standing still on the cold asphalt waiting for the start.
By the time the starting gun sounded I had already been walking and standing in the cold for 20 minutes. My feet were freezing!
After the race I stood around at the finish line waiting for my wife to finish (she was doing the 5K walk). She finished walking about 20 minutes after me, and then we walked the quarter mile back to the car. So in total I spent about an hour and a half barefoot in 32 degree air, but only about 34 minutes running.
If it had been wet, or windy, I would definitely have had some problems!
Certainly got a LOT of comments on my bare feet though!