It actually does get cold here for a few weeks between December and January, much to the surprise of n00bs, but that period has passed as you have already determined.
However the symptoms do match what 80stech has described in the other thread...maybe something else messed up the CCV.
At the end this is all moot now as on the way back to work my X5 decided to commit suicide. Since the engine didn't cut it, it decided to pee the transmission oil and left me stranded on the side of the road. Quite interesting as the two problems can't really be related, can they? Also, the transmission oil lines have been replaced few months ago.
In any case, this did it for me, it is going to the recycler.