I was in Berlin exactly a year ago, and it is indeed unberable. Think bars so filled with smoke you can't see all the way across the room. Smoking outside just wasn't a thing, and it was in the 30s when I was there, so while there is in general a good outdoor drinking culture where you can avoid it for much of the year, in the winter you just can't.

I had to leave some places because it was so unbearable.