Is it ever too cold to be nude? Well, of course. True nudists live by the philosophy " Nude when practical, Clothed when not". I think that sums it up nicely. If it is too cold, there are people who would be upset by your nudity, or similar circumstances, wearing clothing is the way to go.
Right now in Kansas it is COLD!! Snow showers, freezing mist, temps in the high 20's (Fahrenheit), that about sums up the last week and even more. I have been able to sit in front of the woodstove, but had a fall just before Christmas and am not moving too well yet. I decided that being dressed in case someone comes to visit is the best way. So it is practical to wear clothing even though I am home alone all day and would rather be nude. Too much of a chance that someone would come and it would take me too long to get dressed to open the door. So I will just have to wait until I am healed and the weather is warmer to start up being nude around the house again.