I've been riding my Rohloff equipped bicycle for one month now in predominantly freezing temperature, down to -10 C and I am having problems. However, the probleoms are not with the internal gear, but with the cable/external gear change mechanism. First I thought the problem was in the external gear mechanism, but I have now traced it to be moisture in the cables. How that could happen I don't know as they seem to be pretty good covered against water penetration. It started to happen two days after I bought the bicycle so either the wires were moist from the very beginning or the first day of rain did it. The recommendation on the Rohloff web site is to replace the wires and the inner sleeves. I guess I have to do that.
Tore