It will be REALLY COLD. We went in feb last year and there was ice floating down the river! We stayed here and it cost about 112 for two adults, two children for 3 nights, we booked it through booking.com don't know if it would have been more/less to book directly. We had a family room, with a double bed (actually two singles) and a bunkbed, there would have been room for a cot too.
We LOVED berlin, so much so that we're going back this summer for some fun-in-a-lake action. There are plenty of playgrounds, but at that time of year you may prefer the kindercafes which are cafes designed for children to play whilst adults eat cake and are much better than wacky warehouse!
We made the children (5 and 3) do some touristy stuff then went to a playground, then more touristy stuff. It was brilliant.
DH really wants to do a long weekend in mid-December, to drink in the christmassy atmosphere, go along to a couple of christmas markets and chill out. We've got airmiles to use and all looks good. We'll have a 7, nearly 5 year old and 5 month old baby at that stage. I've heard Berlin is quite child friendly - is that right? Any top tips on places/areas to stay and things to do? Any suggestions would be most gratefully accepted!