I was wondering how often random werewolf attacks happen? I encountered a random attack by some Werewolf Beastmasters just recently, the only one in, oh, probably 400 hours of playing Skyrim. It was pretty exciting, and quite challenging too - though that might have been because for the first couple of minutes I was just standing there like a stunned mullet, thinking, "Wait, these are... werewolves?".

So... who else has encountered this? Do they recur?

I think werewolves only occur if you've completed the Proving Honor quest in the Companions.

Thanks. Well, I have completed it, but that was over 100 hours ago. Would love to see more of these.

I've only seen this happen twice, both encounters were at night and far from the main roads. One was in the Reach by the shrine to Peryite and the other time was in the Rift around Redwater Den. So no, they do not happen often. I wish they were more frequent though, werewolves are really fun to fight.