Heh, well weather patterns are different everywhere, but this always happens here in so cal.
We get a small taste of winter, wind/rain/"cold" temps at the end of oct and nov. then very frequently it is very nice in Dec. Including 80 on xmas day like this year. It kind of lulls you. You think, not so bad, and days are getting longer now so winter is over right?
Then comes January, February and March to slap you in the face (and April and May too if at any altitude). And even in So Cal it's a long annoying period of the REAL winter left to go.
Don't let the dec warm-up fool you!