Hi RC
Not been in Dec, but we went in May this year. I expect weather in dec would be nice. We went in may and it was cold for may but it was hot enough for me!!
We got ripped off by the taxi from the airport so watch out for that one. I'm not sure how much its supposed to be so you better check before you go.
Whereabouts are you staying??
Also the sellers can be quite insistant, so be prepared for that, in a souk they wanted £70 for 10 bangles that I didn't even want, eventually my boyfriend paid £7 for 2 bangles, so be prepared to say no thankyou (or arabic equivalent - cant remember what that is)
It is a game for them and you would be fleeced of your money for something you don't want, given half the chance.
That said we had a nice time, just thought i'd give you a warning.
Hope I haven't put you off, i'd go back to Marrakesh!