Anyone traveled to Prague between Christmas and New year
No, but I bet it will be chilly!
FYI, you may get better responses if you repost in the "East" section of the board.
I was there in the first week of January 2006. I'm not sure the crowd situation would be the same, but I can comment on the weather. It will be cold, but not unbearable. Bring a heavy coat, gloves, scarf. And definitely bring good shoes. The streets may be wet, slick with rain or light snow. Some of the hilly parts of town will have slick walkways. Skies are gray.
On my trip I was visiting a friend at Charles University, so I was solo during the morning, met her for lunch, then solo again until dinner time. I loved walking the streets of Prague without the hassle of big crowds. Everything was available to see without long queues. I do feel I missed something, however, not seeing Prague in finer weather. Prague in winter was a great introduction to the city, but I still plan to see it better in spring or fall one year.
Weather will be most likely around freezing, maybe snow or rain showers if you are lucky could be sunshine. Also could be relatively warm or on the other hand very cold. I remember one year minus 30 degrees Celsius. But that's unusual. It's much easier to predict what the weather will be around Christmas in Seattle than in Prague.